strrchr() Function

The strrchr() function in C locates the last occurrence of a specific character within a string. It returns a pointer to that occurrence, allowing you to determine the position of the character from the end of the string. Additionally, since the terminating null-character is considered part of the string, this function can be used to obtain a pointer to the end of the string.

Syntax of strrchr()

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const char *strrchr(const char *str, int character);

Parameters

ParameterDescription
strC string in which to search for the character.
characterThe character to be located. It is passed as an int but converted internally to char.

Return Value

The function returns a pointer to the last occurrence of the specified character within the given string. If the character is not found, it returns a null pointer.

Note that the terminating null-character is considered part of the string. Thus, searching for '\0' will yield a pointer to the end of the string. This behavior can be useful for determining string lengths or for appending characters.

Examples for strrchr()

Example 1: Finding the Last Occurrence of a Character

This example demonstrates how to locate the last occurrence of a character within a string using strrchr().

Program

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#include <stdio.h>
#include <string.h>

int main() {
    const char *text = "hello world";
    const char *ptr = strrchr(text, 'l');
    
    if (ptr != NULL) {
        printf("Last occurrence of 'l': %s\n", ptr);
    } else {
        printf("Character not found.\n");
    }
    
    return 0;
}

Output:

Last occurrence of 'l': ld

Example 2: Character Not Found

This example shows the case where the specified character does not exist in the string, resulting in a null pointer.

Program

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#include <stdio.h>
#include <string.h>

int main() {
    const char *text = "example";
    const char *ptr = strrchr(text, 'z');
    
    if (ptr != NULL) {
        printf("Last occurrence of 'z': %s\n", ptr);
    } else {
        printf("Character not found.\n");
    }
    
    return 0;
}

Output:

Character not found.

Example 3: Locating the Null Terminator

This example demonstrates that searching for the null character returns a pointer to the end of the string.

Program

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#include <stdio.h>
#include <string.h>

int main() {
    const char *text = "Find end";
    const char *ptr = strrchr(text, '\0');
    
    // ptr points to the terminating null character; printing it results in an empty string.
    printf("Pointer to null terminator: %s\n", ptr);
    
    return 0;
}

Output:

Pointer to null terminator: