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Ciągi C++

W C++ string jest obiektem std::string klasa reprezentująca sekwencję znaków. Na ciągach znaków możemy wykonywać wiele operacji takich jak łączenie, porównywanie, konwersja itp.


Przykład ciągu C++

Zobaczmy prosty przykład łańcucha C++.

 #include using namespace std; int main( ) { string s1 = &apos;Hello&apos;; char ch[] = { &apos;C&apos;, &apos;+&apos;, &apos;+&apos;}; string s2 = string(ch); cout&lt;<s1<<endl; cout<<s2<<endl; } < pre> <p>Output:</p> <pre> Hello C++ </pre> <hr> <h2>C++ String Compare Example</h2> <p>Let&apos;s see the simple example of string comparison using strcmp() function.</p> <pre> #include #include using namespace std; int main () { char key[] = &apos;mango&apos;; char buffer[50]; do { cout&lt;&gt;buffer; } while (strcmp (key,buffer) != 0); cout&lt;<'answer is correct!!'<<endl; return 0; } < pre> <p>Output:</p> <pre> What is my favourite fruit? apple What is my favourite fruit? banana What is my favourite fruit? mango Answer is correct!! </pre> <hr> <h2>C++ String Concat Example</h2> <p>Let&apos;s see the simple example of string concatenation using strcat() function.</p> <pre> #include #include using namespace std; int main() { char key[25], buffer[25]; cout &lt;&lt; &apos;Enter the key string: &apos;; cin.getline(key, 25); cout &lt;&lt; &apos;Enter the buffer string: &apos;; cin.getline(buffer, 25); strcat(key, buffer); cout &lt;&lt; &apos;Key = &apos; &lt;&lt; key &lt;&lt; endl; cout &lt;&lt; &apos;Buffer = &apos; &lt;&lt; buffer&lt;<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: Welcome to Enter the buffer string: C++ Programming. Key = Welcome to C++ Programming. Buffer = C++ Programming. </pre> <hr> <h2>C++ String Copy Example</h2> <p>Let&apos;s see the simple example of copy the string using strcpy() function.</p> <pre> #include #include using namespace std; int main() { char key[25], buffer[25]; cout &lt;&lt; &apos;Enter the key string: &apos;; cin.getline(key, 25); strcpy(buffer, key); cout &lt;&lt; &apos;Key = &apos;&lt;&lt; key &lt;&lt; endl; cout &lt;&lt; &apos;Buffer = &apos;&lt;&lt; buffer&lt;<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: C++ Tutorial Key = C++ Tutorial Buffer = C++ Tutorial </pre> <hr> <h2>C++ String Length Example</h2> <p>Let&apos;s see the simple example of finding the string length using strlen() function.</p> <pre> #include #include using namespace std; int main() { char ary[] = &apos;Welcome to C++ Programming&apos;; cout &lt;&lt; &apos;Length of String = &apos; &lt;&lt; strlen(ary)&lt;<endl; return 0; } < pre> <p>Output:</p> <pre> Length of String = 26 </pre> <h2>C++ String Functions</h2> <table class="table"> <tr> <th>Function</th> <th>Description</th> </tr> <tr> <td> int compare(const string&amp; str) </td> <td>It is used to compare two string objects.</td> </tr> <tr> <td> <a href="/c-string-length">int length()</a> </td> <td>It is used to find the length of the string.</td> </tr> <tr> <td> void swap(string&amp; str) </td> <td>It is used to swap the values of two string objects.</td> </tr> <tr> <td>string substr(int pos,int n)</td> <td>It creates a new string object of n characters.</td> </tr> <tr> <td> <a href="/c-string-size">int size()</a> </td> <td>It returns the length of the string in terms of bytes.</td> </tr> <tr> <td> void resize(int n) </td> <td>It is used to resize the length of the string up to n characters.</td> </tr> <tr> <td> <a href="/c-string-replace">string&amp; replace(int pos,int len,string&amp; str)</a> </td> <td>It replaces portion of the string that begins at character position pos and spans len characters.</td> </tr> <tr> <td> <a href="/c-string-append">string&amp; append(const string&amp; str)</a> </td> <td>It adds new characters at the end of another string object.</td> </tr> <tr> <td> char&amp; at(int pos) </td> <td>It is used to access an individual character at specified position pos.</td> </tr> <tr> <td> <a href="/c-string-find">int find(string&amp; str,int pos,int n)</a> </td> <td>It is used to find the string specified in the parameter.</td> </tr> <tr> <td> int find_first_of(string&amp; str,int pos,int n) </td> <td>It is used to find the first occurrence of the specified sequence.</td> </tr> <tr> <td> int find_first_not_of(string&amp; str,int pos,int n ) </td> <td>It is used to search the string for the first character that does not match with any of the characters specified in the string.</td> </tr> <tr> <td> int find_last_of(string&amp; str,int pos,int n) </td> <td>It is used to search the string for the last character of specified sequence.</td> </tr> <tr> <td> int find_last_not_of(string&amp; str,int pos) </td> <td>It searches for the last character that does not match with the specified sequence.</td> </tr> <tr> <td> string&amp; insert() </td> <td>It inserts a new character before the character indicated by the position pos.</td> </tr> <tr> <td> int max_size() </td> <td>It finds the maximum length of the string.</td> </tr> <tr> <td> <a href="/c-string-push_back">void push_back(char ch)</a> </td> <td>It adds a new character ch at the end of the string.</td> </tr> <tr> <td> void pop_back() </td> <td>It removes a last character of the string.</td> </tr> <tr> <td> <a href="/c-string-assign">string&amp; assign()</a> </td> <td>It assigns new value to the string.</td> </tr> <tr> <td> int copy(string&amp; str) </td> <td>It copies the contents of string into another.</td> </tr> <tr> <td> char&amp; back() </td> <td>It returns the reference of last character.</td> </tr> <tr> <td> Iterator begin() </td> <td>It returns the reference of first character.</td> </tr> <tr> <td> int capacity() </td> <td>It returns the allocated space for the string.</td> </tr> <tr> <td>const_iterator cbegin()</td> <td>It points to the first element of the string.</td> </tr> <tr> <td>const_iterator cend()</td> <td>It points to the last element of the string.</td> </tr> <tr> <td>void clear()</td> <td>It removes all the elements from the string.</td> </tr> <tr> <td>const_reverse_iterator crbegin()</td> <td>It points to the last character of the string.</td> </tr> <tr> <td>const_char* data()</td> <td>It copies the characters of string into an array.</td> </tr> <tr> <td>bool empty()</td> <td>It checks whether the string is empty or not.</td> </tr> <tr> <td>string&amp; erase()</td> <td>It removes the characters as specified.</td> </tr> <tr> <td> char&amp; front() </td> <td>It returns a reference of the first character.</td> </tr> <tr> <td> string&amp;&#xFFFD; operator+=() </td> <td>It appends a new character at the end of the string.</td> </tr> <tr> <td> string&amp; operator=() </td> <td>It assigns a new value to the string.</td> </tr> <tr> <td>char operator[](pos)</td> <td>It retrieves a character at specified position pos.</td> </tr> <tr> <td> int rfind() </td> <td>It searches for the last occurrence of the string.</td> </tr> <tr> <td> iterator end() </td> <td>It references the last character of the string.</td> </tr> <tr> <td> reverse_iterator rend() </td> <td>It points to the first character of the string.</td> </tr> <tr> <td> void shrink_to_fit() </td> <td>It reduces the capacity and makes it equal to the size of the string.</td> </tr> <tr> <td> char* c_str() </td> <td>It returns pointer to an array that contains null terminated sequence of characters.</td> </tr> <tr> <td> const_reverse_iterator crend() </td> <td>It references the first character of the string.</td> </tr> <tr> <td> reverse_iterator rbegin() </td> <td>It reference the last character of the string.</td> </tr> <tr> <td>void reserve(inr len)</td> <td>It requests a change in capacity.</td> </tr> <tr> <td>allocator_type get_allocator();</td> <td>It returns the allocated object associated with the string.</td> </tr> </table></endl;></pre></endl;></pre></endl;></pre></'answer></pre></s1<<endl;>

Przykład porównania ciągów C++

Zobaczmy prosty przykład porównania ciągów znaków przy użyciu funkcji strcmp().

 #include #include using namespace std; int main () { char key[] = &apos;mango&apos;; char buffer[50]; do { cout&lt;&gt;buffer; } while (strcmp (key,buffer) != 0); cout&lt;<\'answer is correct!!\'<<endl; return 0; } < pre> <p>Output:</p> <pre> What is my favourite fruit? apple What is my favourite fruit? banana What is my favourite fruit? mango Answer is correct!! </pre> <hr> <h2>C++ String Concat Example</h2> <p>Let&apos;s see the simple example of string concatenation using strcat() function.</p> <pre> #include #include using namespace std; int main() { char key[25], buffer[25]; cout &lt;&lt; &apos;Enter the key string: &apos;; cin.getline(key, 25); cout &lt;&lt; &apos;Enter the buffer string: &apos;; cin.getline(buffer, 25); strcat(key, buffer); cout &lt;&lt; &apos;Key = &apos; &lt;&lt; key &lt;&lt; endl; cout &lt;&lt; &apos;Buffer = &apos; &lt;&lt; buffer&lt;<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: Welcome to Enter the buffer string: C++ Programming. Key = Welcome to C++ Programming. Buffer = C++ Programming. </pre> <hr> <h2>C++ String Copy Example</h2> <p>Let&apos;s see the simple example of copy the string using strcpy() function.</p> <pre> #include #include using namespace std; int main() { char key[25], buffer[25]; cout &lt;&lt; &apos;Enter the key string: &apos;; cin.getline(key, 25); strcpy(buffer, key); cout &lt;&lt; &apos;Key = &apos;&lt;&lt; key &lt;&lt; endl; cout &lt;&lt; &apos;Buffer = &apos;&lt;&lt; buffer&lt;<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: C++ Tutorial Key = C++ Tutorial Buffer = C++ Tutorial </pre> <hr> <h2>C++ String Length Example</h2> <p>Let&apos;s see the simple example of finding the string length using strlen() function.</p> <pre> #include #include using namespace std; int main() { char ary[] = &apos;Welcome to C++ Programming&apos;; cout &lt;&lt; &apos;Length of String = &apos; &lt;&lt; strlen(ary)&lt;<endl; return 0; } < pre> <p>Output:</p> <pre> Length of String = 26 </pre> <h2>C++ String Functions</h2> <table class="table"> <tr> <th>Function</th> <th>Description</th> </tr> <tr> <td> int compare(const string&amp; str) </td> <td>It is used to compare two string objects.</td> </tr> <tr> <td> <a href="/c-string-length">int length()</a> </td> <td>It is used to find the length of the string.</td> </tr> <tr> <td> void swap(string&amp; str) </td> <td>It is used to swap the values of two string objects.</td> </tr> <tr> <td>string substr(int pos,int n)</td> <td>It creates a new string object of n characters.</td> </tr> <tr> <td> <a href="/c-string-size">int size()</a> </td> <td>It returns the length of the string in terms of bytes.</td> </tr> <tr> <td> void resize(int n) </td> <td>It is used to resize the length of the string up to n characters.</td> </tr> <tr> <td> <a href="/c-string-replace">string&amp; replace(int pos,int len,string&amp; str)</a> </td> <td>It replaces portion of the string that begins at character position pos and spans len characters.</td> </tr> <tr> <td> <a href="/c-string-append">string&amp; append(const string&amp; str)</a> </td> <td>It adds new characters at the end of another string object.</td> </tr> <tr> <td> char&amp; at(int pos) </td> <td>It is used to access an individual character at specified position pos.</td> </tr> <tr> <td> <a href="/c-string-find">int find(string&amp; str,int pos,int n)</a> </td> <td>It is used to find the string specified in the parameter.</td> </tr> <tr> <td> int find_first_of(string&amp; str,int pos,int n) </td> <td>It is used to find the first occurrence of the specified sequence.</td> </tr> <tr> <td> int find_first_not_of(string&amp; str,int pos,int n ) </td> <td>It is used to search the string for the first character that does not match with any of the characters specified in the string.</td> </tr> <tr> <td> int find_last_of(string&amp; str,int pos,int n) </td> <td>It is used to search the string for the last character of specified sequence.</td> </tr> <tr> <td> int find_last_not_of(string&amp; str,int pos) </td> <td>It searches for the last character that does not match with the specified sequence.</td> </tr> <tr> <td> string&amp; insert() </td> <td>It inserts a new character before the character indicated by the position pos.</td> </tr> <tr> <td> int max_size() </td> <td>It finds the maximum length of the string.</td> </tr> <tr> <td> <a href="/c-string-push_back">void push_back(char ch)</a> </td> <td>It adds a new character ch at the end of the string.</td> </tr> <tr> <td> void pop_back() </td> <td>It removes a last character of the string.</td> </tr> <tr> <td> <a href="/c-string-assign">string&amp; assign()</a> </td> <td>It assigns new value to the string.</td> </tr> <tr> <td> int copy(string&amp; str) </td> <td>It copies the contents of string into another.</td> </tr> <tr> <td> char&amp; back() </td> <td>It returns the reference of last character.</td> </tr> <tr> <td> Iterator begin() </td> <td>It returns the reference of first character.</td> </tr> <tr> <td> int capacity() </td> <td>It returns the allocated space for the string.</td> </tr> <tr> <td>const_iterator cbegin()</td> <td>It points to the first element of the string.</td> </tr> <tr> <td>const_iterator cend()</td> <td>It points to the last element of the string.</td> </tr> <tr> <td>void clear()</td> <td>It removes all the elements from the string.</td> </tr> <tr> <td>const_reverse_iterator crbegin()</td> <td>It points to the last character of the string.</td> </tr> <tr> <td>const_char* data()</td> <td>It copies the characters of string into an array.</td> </tr> <tr> <td>bool empty()</td> <td>It checks whether the string is empty or not.</td> </tr> <tr> <td>string&amp; erase()</td> <td>It removes the characters as specified.</td> </tr> <tr> <td> char&amp; front() </td> <td>It returns a reference of the first character.</td> </tr> <tr> <td> string&amp;&#xFFFD; operator+=() </td> <td>It appends a new character at the end of the string.</td> </tr> <tr> <td> string&amp; operator=() </td> <td>It assigns a new value to the string.</td> </tr> <tr> <td>char operator[](pos)</td> <td>It retrieves a character at specified position pos.</td> </tr> <tr> <td> int rfind() </td> <td>It searches for the last occurrence of the string.</td> </tr> <tr> <td> iterator end() </td> <td>It references the last character of the string.</td> </tr> <tr> <td> reverse_iterator rend() </td> <td>It points to the first character of the string.</td> </tr> <tr> <td> void shrink_to_fit() </td> <td>It reduces the capacity and makes it equal to the size of the string.</td> </tr> <tr> <td> char* c_str() </td> <td>It returns pointer to an array that contains null terminated sequence of characters.</td> </tr> <tr> <td> const_reverse_iterator crend() </td> <td>It references the first character of the string.</td> </tr> <tr> <td> reverse_iterator rbegin() </td> <td>It reference the last character of the string.</td> </tr> <tr> <td>void reserve(inr len)</td> <td>It requests a change in capacity.</td> </tr> <tr> <td>allocator_type get_allocator();</td> <td>It returns the allocated object associated with the string.</td> </tr> </table></endl;></pre></endl;></pre></endl;></pre></\'answer>

Przykład łączenia ciągów C++

Zobaczmy prosty przykład łączenia ciągów znaków przy użyciu funkcji strcat().

polecenie cp w systemie Linux
 #include #include using namespace std; int main() { char key[25], buffer[25]; cout &lt;&lt; &apos;Enter the key string: &apos;; cin.getline(key, 25); cout &lt;&lt; &apos;Enter the buffer string: &apos;; cin.getline(buffer, 25); strcat(key, buffer); cout &lt;&lt; &apos;Key = &apos; &lt;&lt; key &lt;&lt; endl; cout &lt;&lt; &apos;Buffer = &apos; &lt;&lt; buffer&lt;<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: Welcome to Enter the buffer string: C++ Programming. Key = Welcome to C++ Programming. Buffer = C++ Programming. </pre> <hr> <h2>C++ String Copy Example</h2> <p>Let&apos;s see the simple example of copy the string using strcpy() function.</p> <pre> #include #include using namespace std; int main() { char key[25], buffer[25]; cout &lt;&lt; &apos;Enter the key string: &apos;; cin.getline(key, 25); strcpy(buffer, key); cout &lt;&lt; &apos;Key = &apos;&lt;&lt; key &lt;&lt; endl; cout &lt;&lt; &apos;Buffer = &apos;&lt;&lt; buffer&lt;<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: C++ Tutorial Key = C++ Tutorial Buffer = C++ Tutorial </pre> <hr> <h2>C++ String Length Example</h2> <p>Let&apos;s see the simple example of finding the string length using strlen() function.</p> <pre> #include #include using namespace std; int main() { char ary[] = &apos;Welcome to C++ Programming&apos;; cout &lt;&lt; &apos;Length of String = &apos; &lt;&lt; strlen(ary)&lt;<endl; return 0; } < pre> <p>Output:</p> <pre> Length of String = 26 </pre> <h2>C++ String Functions</h2> <table class="table"> <tr> <th>Function</th> <th>Description</th> </tr> <tr> <td> int compare(const string&amp; str) </td> <td>It is used to compare two string objects.</td> </tr> <tr> <td> <a href="/c-string-length">int length()</a> </td> <td>It is used to find the length of the string.</td> </tr> <tr> <td> void swap(string&amp; str) </td> <td>It is used to swap the values of two string objects.</td> </tr> <tr> <td>string substr(int pos,int n)</td> <td>It creates a new string object of n characters.</td> </tr> <tr> <td> <a href="/c-string-size">int size()</a> </td> <td>It returns the length of the string in terms of bytes.</td> </tr> <tr> <td> void resize(int n) </td> <td>It is used to resize the length of the string up to n characters.</td> </tr> <tr> <td> <a href="/c-string-replace">string&amp; replace(int pos,int len,string&amp; str)</a> </td> <td>It replaces portion of the string that begins at character position pos and spans len characters.</td> </tr> <tr> <td> <a href="/c-string-append">string&amp; append(const string&amp; str)</a> </td> <td>It adds new characters at the end of another string object.</td> </tr> <tr> <td> char&amp; at(int pos) </td> <td>It is used to access an individual character at specified position pos.</td> </tr> <tr> <td> <a href="/c-string-find">int find(string&amp; str,int pos,int n)</a> </td> <td>It is used to find the string specified in the parameter.</td> </tr> <tr> <td> int find_first_of(string&amp; str,int pos,int n) </td> <td>It is used to find the first occurrence of the specified sequence.</td> </tr> <tr> <td> int find_first_not_of(string&amp; str,int pos,int n ) </td> <td>It is used to search the string for the first character that does not match with any of the characters specified in the string.</td> </tr> <tr> <td> int find_last_of(string&amp; str,int pos,int n) </td> <td>It is used to search the string for the last character of specified sequence.</td> </tr> <tr> <td> int find_last_not_of(string&amp; str,int pos) </td> <td>It searches for the last character that does not match with the specified sequence.</td> </tr> <tr> <td> string&amp; insert() </td> <td>It inserts a new character before the character indicated by the position pos.</td> </tr> <tr> <td> int max_size() </td> <td>It finds the maximum length of the string.</td> </tr> <tr> <td> <a href="/c-string-push_back">void push_back(char ch)</a> </td> <td>It adds a new character ch at the end of the string.</td> </tr> <tr> <td> void pop_back() </td> <td>It removes a last character of the string.</td> </tr> <tr> <td> <a href="/c-string-assign">string&amp; assign()</a> </td> <td>It assigns new value to the string.</td> </tr> <tr> <td> int copy(string&amp; str) </td> <td>It copies the contents of string into another.</td> </tr> <tr> <td> char&amp; back() </td> <td>It returns the reference of last character.</td> </tr> <tr> <td> Iterator begin() </td> <td>It returns the reference of first character.</td> </tr> <tr> <td> int capacity() </td> <td>It returns the allocated space for the string.</td> </tr> <tr> <td>const_iterator cbegin()</td> <td>It points to the first element of the string.</td> </tr> <tr> <td>const_iterator cend()</td> <td>It points to the last element of the string.</td> </tr> <tr> <td>void clear()</td> <td>It removes all the elements from the string.</td> </tr> <tr> <td>const_reverse_iterator crbegin()</td> <td>It points to the last character of the string.</td> </tr> <tr> <td>const_char* data()</td> <td>It copies the characters of string into an array.</td> </tr> <tr> <td>bool empty()</td> <td>It checks whether the string is empty or not.</td> </tr> <tr> <td>string&amp; erase()</td> <td>It removes the characters as specified.</td> </tr> <tr> <td> char&amp; front() </td> <td>It returns a reference of the first character.</td> </tr> <tr> <td> string&amp;&#xFFFD; operator+=() </td> <td>It appends a new character at the end of the string.</td> </tr> <tr> <td> string&amp; operator=() </td> <td>It assigns a new value to the string.</td> </tr> <tr> <td>char operator[](pos)</td> <td>It retrieves a character at specified position pos.</td> </tr> <tr> <td> int rfind() </td> <td>It searches for the last occurrence of the string.</td> </tr> <tr> <td> iterator end() </td> <td>It references the last character of the string.</td> </tr> <tr> <td> reverse_iterator rend() </td> <td>It points to the first character of the string.</td> </tr> <tr> <td> void shrink_to_fit() </td> <td>It reduces the capacity and makes it equal to the size of the string.</td> </tr> <tr> <td> char* c_str() </td> <td>It returns pointer to an array that contains null terminated sequence of characters.</td> </tr> <tr> <td> const_reverse_iterator crend() </td> <td>It references the first character of the string.</td> </tr> <tr> <td> reverse_iterator rbegin() </td> <td>It reference the last character of the string.</td> </tr> <tr> <td>void reserve(inr len)</td> <td>It requests a change in capacity.</td> </tr> <tr> <td>allocator_type get_allocator();</td> <td>It returns the allocated object associated with the string.</td> </tr> </table></endl;></pre></endl;></pre></endl;>

Przykład kopiowania ciągu C++

Zobaczmy prosty przykład kopiowania ciągu za pomocą funkcji strcpy().

 #include #include using namespace std; int main() { char key[25], buffer[25]; cout &lt;&lt; &apos;Enter the key string: &apos;; cin.getline(key, 25); strcpy(buffer, key); cout &lt;&lt; &apos;Key = &apos;&lt;&lt; key &lt;&lt; endl; cout &lt;&lt; &apos;Buffer = &apos;&lt;&lt; buffer&lt;<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: C++ Tutorial Key = C++ Tutorial Buffer = C++ Tutorial </pre> <hr> <h2>C++ String Length Example</h2> <p>Let&apos;s see the simple example of finding the string length using strlen() function.</p> <pre> #include #include using namespace std; int main() { char ary[] = &apos;Welcome to C++ Programming&apos;; cout &lt;&lt; &apos;Length of String = &apos; &lt;&lt; strlen(ary)&lt;<endl; return 0; } < pre> <p>Output:</p> <pre> Length of String = 26 </pre> <h2>C++ String Functions</h2> <table class="table"> <tr> <th>Function</th> <th>Description</th> </tr> <tr> <td> int compare(const string&amp; str) </td> <td>It is used to compare two string objects.</td> </tr> <tr> <td> <a href="/c-string-length">int length()</a> </td> <td>It is used to find the length of the string.</td> </tr> <tr> <td> void swap(string&amp; str) </td> <td>It is used to swap the values of two string objects.</td> </tr> <tr> <td>string substr(int pos,int n)</td> <td>It creates a new string object of n characters.</td> </tr> <tr> <td> <a href="/c-string-size">int size()</a> </td> <td>It returns the length of the string in terms of bytes.</td> </tr> <tr> <td> void resize(int n) </td> <td>It is used to resize the length of the string up to n characters.</td> </tr> <tr> <td> <a href="/c-string-replace">string&amp; replace(int pos,int len,string&amp; str)</a> </td> <td>It replaces portion of the string that begins at character position pos and spans len characters.</td> </tr> <tr> <td> <a href="/c-string-append">string&amp; append(const string&amp; str)</a> </td> <td>It adds new characters at the end of another string object.</td> </tr> <tr> <td> char&amp; at(int pos) </td> <td>It is used to access an individual character at specified position pos.</td> </tr> <tr> <td> <a href="/c-string-find">int find(string&amp; str,int pos,int n)</a> </td> <td>It is used to find the string specified in the parameter.</td> </tr> <tr> <td> int find_first_of(string&amp; str,int pos,int n) </td> <td>It is used to find the first occurrence of the specified sequence.</td> </tr> <tr> <td> int find_first_not_of(string&amp; str,int pos,int n ) </td> <td>It is used to search the string for the first character that does not match with any of the characters specified in the string.</td> </tr> <tr> <td> int find_last_of(string&amp; str,int pos,int n) </td> <td>It is used to search the string for the last character of specified sequence.</td> </tr> <tr> <td> int find_last_not_of(string&amp; str,int pos) </td> <td>It searches for the last character that does not match with the specified sequence.</td> </tr> <tr> <td> string&amp; insert() </td> <td>It inserts a new character before the character indicated by the position pos.</td> </tr> <tr> <td> int max_size() </td> <td>It finds the maximum length of the string.</td> </tr> <tr> <td> <a href="/c-string-push_back">void push_back(char ch)</a> </td> <td>It adds a new character ch at the end of the string.</td> </tr> <tr> <td> void pop_back() </td> <td>It removes a last character of the string.</td> </tr> <tr> <td> <a href="/c-string-assign">string&amp; assign()</a> </td> <td>It assigns new value to the string.</td> </tr> <tr> <td> int copy(string&amp; str) </td> <td>It copies the contents of string into another.</td> </tr> <tr> <td> char&amp; back() </td> <td>It returns the reference of last character.</td> </tr> <tr> <td> Iterator begin() </td> <td>It returns the reference of first character.</td> </tr> <tr> <td> int capacity() </td> <td>It returns the allocated space for the string.</td> </tr> <tr> <td>const_iterator cbegin()</td> <td>It points to the first element of the string.</td> </tr> <tr> <td>const_iterator cend()</td> <td>It points to the last element of the string.</td> </tr> <tr> <td>void clear()</td> <td>It removes all the elements from the string.</td> </tr> <tr> <td>const_reverse_iterator crbegin()</td> <td>It points to the last character of the string.</td> </tr> <tr> <td>const_char* data()</td> <td>It copies the characters of string into an array.</td> </tr> <tr> <td>bool empty()</td> <td>It checks whether the string is empty or not.</td> </tr> <tr> <td>string&amp; erase()</td> <td>It removes the characters as specified.</td> </tr> <tr> <td> char&amp; front() </td> <td>It returns a reference of the first character.</td> </tr> <tr> <td> string&amp;&#xFFFD; operator+=() </td> <td>It appends a new character at the end of the string.</td> </tr> <tr> <td> string&amp; operator=() </td> <td>It assigns a new value to the string.</td> </tr> <tr> <td>char operator[](pos)</td> <td>It retrieves a character at specified position pos.</td> </tr> <tr> <td> int rfind() </td> <td>It searches for the last occurrence of the string.</td> </tr> <tr> <td> iterator end() </td> <td>It references the last character of the string.</td> </tr> <tr> <td> reverse_iterator rend() </td> <td>It points to the first character of the string.</td> </tr> <tr> <td> void shrink_to_fit() </td> <td>It reduces the capacity and makes it equal to the size of the string.</td> </tr> <tr> <td> char* c_str() </td> <td>It returns pointer to an array that contains null terminated sequence of characters.</td> </tr> <tr> <td> const_reverse_iterator crend() </td> <td>It references the first character of the string.</td> </tr> <tr> <td> reverse_iterator rbegin() </td> <td>It reference the last character of the string.</td> </tr> <tr> <td>void reserve(inr len)</td> <td>It requests a change in capacity.</td> </tr> <tr> <td>allocator_type get_allocator();</td> <td>It returns the allocated object associated with the string.</td> </tr> </table></endl;></pre></endl;>

Przykład długości łańcucha C++

Zobaczmy prosty przykład znajdowania długości łańcucha za pomocą funkcji strlen().

 #include #include using namespace std; int main() { char ary[] = &apos;Welcome to C++ Programming&apos;; cout &lt;&lt; &apos;Length of String = &apos; &lt;&lt; strlen(ary)&lt;<endl; return 0; } < pre> <p>Output:</p> <pre> Length of String = 26 </pre> <h2>C++ String Functions</h2> <table class="table"> <tr> <th>Function</th> <th>Description</th> </tr> <tr> <td> int compare(const string&amp; str) </td> <td>It is used to compare two string objects.</td> </tr> <tr> <td> <a href="/c-string-length">int length()</a> </td> <td>It is used to find the length of the string.</td> </tr> <tr> <td> void swap(string&amp; str) </td> <td>It is used to swap the values of two string objects.</td> </tr> <tr> <td>string substr(int pos,int n)</td> <td>It creates a new string object of n characters.</td> </tr> <tr> <td> <a href="/c-string-size">int size()</a> </td> <td>It returns the length of the string in terms of bytes.</td> </tr> <tr> <td> void resize(int n) </td> <td>It is used to resize the length of the string up to n characters.</td> </tr> <tr> <td> <a href="/c-string-replace">string&amp; replace(int pos,int len,string&amp; str)</a> </td> <td>It replaces portion of the string that begins at character position pos and spans len characters.</td> </tr> <tr> <td> <a href="/c-string-append">string&amp; append(const string&amp; str)</a> </td> <td>It adds new characters at the end of another string object.</td> </tr> <tr> <td> char&amp; at(int pos) </td> <td>It is used to access an individual character at specified position pos.</td> </tr> <tr> <td> <a href="/c-string-find">int find(string&amp; str,int pos,int n)</a> </td> <td>It is used to find the string specified in the parameter.</td> </tr> <tr> <td> int find_first_of(string&amp; str,int pos,int n) </td> <td>It is used to find the first occurrence of the specified sequence.</td> </tr> <tr> <td> int find_first_not_of(string&amp; str,int pos,int n ) </td> <td>It is used to search the string for the first character that does not match with any of the characters specified in the string.</td> </tr> <tr> <td> int find_last_of(string&amp; str,int pos,int n) </td> <td>It is used to search the string for the last character of specified sequence.</td> </tr> <tr> <td> int find_last_not_of(string&amp; str,int pos) </td> <td>It searches for the last character that does not match with the specified sequence.</td> </tr> <tr> <td> string&amp; insert() </td> <td>It inserts a new character before the character indicated by the position pos.</td> </tr> <tr> <td> int max_size() </td> <td>It finds the maximum length of the string.</td> </tr> <tr> <td> <a href="/c-string-push_back">void push_back(char ch)</a> </td> <td>It adds a new character ch at the end of the string.</td> </tr> <tr> <td> void pop_back() </td> <td>It removes a last character of the string.</td> </tr> <tr> <td> <a href="/c-string-assign">string&amp; assign()</a> </td> <td>It assigns new value to the string.</td> </tr> <tr> <td> int copy(string&amp; str) </td> <td>It copies the contents of string into another.</td> </tr> <tr> <td> char&amp; back() </td> <td>It returns the reference of last character.</td> </tr> <tr> <td> Iterator begin() </td> <td>It returns the reference of first character.</td> </tr> <tr> <td> int capacity() </td> <td>It returns the allocated space for the string.</td> </tr> <tr> <td>const_iterator cbegin()</td> <td>It points to the first element of the string.</td> </tr> <tr> <td>const_iterator cend()</td> <td>It points to the last element of the string.</td> </tr> <tr> <td>void clear()</td> <td>It removes all the elements from the string.</td> </tr> <tr> <td>const_reverse_iterator crbegin()</td> <td>It points to the last character of the string.</td> </tr> <tr> <td>const_char* data()</td> <td>It copies the characters of string into an array.</td> </tr> <tr> <td>bool empty()</td> <td>It checks whether the string is empty or not.</td> </tr> <tr> <td>string&amp; erase()</td> <td>It removes the characters as specified.</td> </tr> <tr> <td> char&amp; front() </td> <td>It returns a reference of the first character.</td> </tr> <tr> <td> string&amp;&#xFFFD; operator+=() </td> <td>It appends a new character at the end of the string.</td> </tr> <tr> <td> string&amp; operator=() </td> <td>It assigns a new value to the string.</td> </tr> <tr> <td>char operator[](pos)</td> <td>It retrieves a character at specified position pos.</td> </tr> <tr> <td> int rfind() </td> <td>It searches for the last occurrence of the string.</td> </tr> <tr> <td> iterator end() </td> <td>It references the last character of the string.</td> </tr> <tr> <td> reverse_iterator rend() </td> <td>It points to the first character of the string.</td> </tr> <tr> <td> void shrink_to_fit() </td> <td>It reduces the capacity and makes it equal to the size of the string.</td> </tr> <tr> <td> char* c_str() </td> <td>It returns pointer to an array that contains null terminated sequence of characters.</td> </tr> <tr> <td> const_reverse_iterator crend() </td> <td>It references the first character of the string.</td> </tr> <tr> <td> reverse_iterator rbegin() </td> <td>It reference the last character of the string.</td> </tr> <tr> <td>void reserve(inr len)</td> <td>It requests a change in capacity.</td> </tr> <tr> <td>allocator_type get_allocator();</td> <td>It returns the allocated object associated with the string.</td> </tr> </table></endl;>

Funkcje łańcuchowe C++

Funkcjonować Opis
int porównaj (ciąg stały i str) Służy do porównywania dwóch obiektów typu string.
długość całkowita() Służy do znalezienia długości łańcucha.
nieważna zamiana (ciąg i str) Służy do zamiany wartości dwóch obiektów typu string.
string substr(int poz,int n) Tworzy nowy obiekt typu string składający się z n znaków.
rozmiar całkowity() Zwraca długość ciągu w bajtach.
nieważna zmiana rozmiaru (int n) Służy do zmiany długości łańcucha do n znaków.
ciąg i zamień (int poz, int len, ciąg i str) Zastępuje część łańcucha rozpoczynającą się od pozycji znaku i obejmującą długość znaków.
ciąg i dołączenie (ciąg stały i str) Dodaje nowe znaki na końcu innego obiektu typu string.
znak&at(int poz) Służy do dostępu do pojedynczego znaku w określonej pozycji.
int find(string&str,int pozycja,int n) Służy do znalezienia ciągu określonego w parametrze.
int find_first_of(string& str,int pozycja,int n) Służy do znalezienia pierwszego wystąpienia określonej sekwencji.
int find_first_not_of(string& str,int poz,int n ) Służy do przeszukiwania ciągu pod kątem pierwszego znaku, który nie pasuje do żadnego ze znaków określonych w ciągu.
int find_last_of(string& str,int pozycja,int n) Służy do wyszukiwania w ciągu ostatniego znaku określonej sekwencji.
int find_last_not_of(string& str,int pozycja) Wyszukuje ostatni znak, który nie pasuje do określonej sekwencji.
ciąg i wstaw() Wstawia nowy znak przed znakiem wskazanym przez pozycję poz.
int maksymalny_rozmiar() Znajduje maksymalną długość ciągu.
void push_back(char ch) Dodaje nowy znak ch na końcu ciągu.
unieważnij pop_back() Usuwa ostatni znak ciągu.
ciąg&przypisz() Przypisuje nową wartość do ciągu.
int kopia (ciąg i str) Kopiuje zawartość ciągu do innego.
znak i powrót() Zwraca referencję do ostatniego znaku.
Początek iteratora() Zwraca referencję pierwszego znaku.
całkowita pojemność() Zwraca przydzielone miejsce na ciąg.
const_iterator cbegin() Wskazuje na pierwszy element ciągu.
const_iterator cend() Wskazuje na ostatni element ciągu.
puste jasne() Usuwa wszystkie elementy z ciągu.
const_reverse_iterator crbegin() Wskazuje na ostatni znak ciągu.
const_char* dane() Kopiuje znaki ciągu do tablicy.
bool pusty() Sprawdza, czy ciąg znaków jest pusty, czy nie.
ciąg i usuwanie() Usuwa określone znaki.
znak i przód() Zwraca referencję pierwszego znaku.
operator string&�+=() Dodaje nowy znak na końcu ciągu.
ciąg&operator=() Przypisuje nową wartość do ciągu.
operator znaku[](pos) Pobiera znak z określonej pozycji poz.
int rfind() Wyszukuje ostatnie wystąpienie ciągu.
koniec iteratora() Odwołuje się do ostatniego znaku ciągu.
Reverse_iterator rend() Wskazuje na pierwszy znak ciągu.
unieważnij skurcz_to_fit() Zmniejsza pojemność i zrównuje ją z rozmiarem sznurka.
znak* c_str() Zwraca wskaźnik do tablicy zawierającej sekwencję znaków zakończoną znakiem null.
const_reverse_iterator crend() Odwołuje się do pierwszego znaku ciągu.
Reverse_iterator rbegin() Odwołuje się do ostatniego znaku ciągu.
nieważna rezerwa (inr len) Żąda zmiany pojemności.
typ_alokatora get_allocator(); Zwraca przydzielony obiekt powiązany z ciągiem znaków.