strchr() in C: Find a Character

strchr() searches a string for the first occurrence of a character. It returns a pointer to the matching character, or NULL when no match exists.

Syntax Top ↑

char *match = strchr(string, character);

Find the First Matching Character Top ↑

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

int main(void) {
    char text[] = "Welcome to plus2net";
    char *match = strchr(text, 'm');

    if (match != NULL) {
        size_t position = (size_t)(match - text);
        printf("Character: %c\n", *match);
        printf("Zero-based position: %zu\n", position);
        printf("From the match: %s\n", match);
    }

    return 0;
}

Always Check for NULL Before Dereferencing Top ↑

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

int main(void) {
    char text[] = "C programming is fun!";
    char target = 'z';
    char *match = strchr(text, target);

    if (match != NULL) {
        printf("Found %c.\n", *match);
    } else {
        printf("Character not found.\n");
    }

    return 0;
}

Dereferencing a NULL pointer with *match is invalid, so the pointer must be checked first.

Search User Input Top ↑

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

int main(void) {
    char text[100];
    char target;

    printf("Enter a string: ");
    if (fgets(text, sizeof(text), stdin) == NULL) {
        return 1;
    }
    text[strcspn(text, "\n")] = '\0';

    printf("Enter a character: ");
    if (scanf(" %c", &target) != 1) {
        return 1;
    }

    char *match = strchr(text, target);
    if (match != NULL) {
        printf("Found at zero-based position %zu.\n", (size_t)(match - text));
    } else {
        printf("Character not found.\n");
    }

    return 0;
}

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

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