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

int main(int argc, char **argv) {
    const char *fileName = "/home/maku/sample.txt";
    const char *ext = strrchr(fileName, '.');

    if (ext) {
        printf("Extension is %s\n", ext);
    } else {
        printf("No extension\n");
    }

    return 0;
}