Question

How to get a file extension from a file path in C

Answer 1

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

const char* get_filename_ext(const char* filename) {
    const char* dot = strrchr(filename, '.');

    if (!dot || dot == filename) { // example: dot == filename // "."
        return "";
    }
    
    return dot + 1;
}

int main() {

    printf("1 %s\n", get_filename_ext("test.exe"));
    printf("2 %s\n", get_filename_ext("test.io"));
    printf("3 %s\n", get_filename_ext("test.jpeg"));
    printf("4 %s\n", get_filename_ext("test."));
    printf("5 %s\n", get_filename_ext("test"));
    printf("6 %s\n", get_filename_ext("..."));
    printf("7 %s\n", get_filename_ext("test.o"));
    printf("8 %s\n", get_filename_ext("test.en.zip"));
    printf("9 %s\n", get_filename_ext("."));
    printf("10 %s\n", get_filename_ext(""));

    return 0;
}




/*
run:

1 exe
2 io
3 jpeg
4
5
6
7 o
8 zip
9
10

*/

 

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