format st_mtime which get from stat()

format_st_mtime.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <time.h>

int main(int argc, char *argv[])
{
    struct stat st;
    char *f = "README";
    if (stat(f, &st) == -1) {
        perror("stat");
        exit(1);
    }
    char mtime[80];
    time_t t = st.st_mtime; /*st_mtime is type time_t */
    struct tm lt;
    localtime_r(&t, &lt); /* convert to struct tm */
    strftime(mtime, sizeof mtime, "%a, %d %b %Y %T", &lt);
    printf("%s\n", mtime);
    return 0;
}