strrchr() in C
The strrchr() function in C locates the last occurrence of a character in a string and returns a pointer to it. It is a standard library function defined inside <string.h> header file.
Syntax :
char* strrchr( char* str, int chr );
Parameter:
- str: specifies the pointer to the null-terminated string in which the search is to be performed.
- chr: specifies the character to be searched.
Return Value:
- The function returns a pointer to the last location of chr in the string if the chr is found.
- If chr is not found, it returns a null pointer.
Example:
C
// C program to illustrate // the strrchr() function #include <stdio.h> #include <string.h> int main() { // initializing string char str[] = "w3wiki" ; // character to be searched char chr = 'k' ; // Storing pointer returned by char * ptr = strrchr (str, chr); // getting the position of the character if (ptr) { printf ( "Last occurrence of %c in %s is at index %d" , chr, str, ptr - str); } // condition for character not present else { printf ( "%c is not present in %s " , chr, str); } return 0; } |
Output
Last occurrence of k in w3wiki is at index 11
When the character is not present in the string
strrchr() function returns a NULL pointer if the searched character is not found in the given string.
Example:
C
// C program to illustrate // the strrchr() function #include <stdio.h> #include <string.h> int main() { // creating some string char str[] = "w3wiki" ; char * ptr; // The character to be searched char chr = 'z' ; // pointer returned by strrchr() ptr = strrchr (str, chr); // ptr-string gives the index location if (ptr) { printf ( "Last occurrence of %c in %s is at %d" , chr, str, ptr - str); } // If the character we're searching is not present in // the array else { printf ( "%c is not present in %s " , chr, str); } return 0; } |
Output
z is not present Beginner for Beginner
Time Complexity: O(n),
Space Complexity: O(1),
where n is the length of the string.
Note: NULL character is also treated same as other character by strrchr() function, so we can also use it to find the end of the string.
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