#include<stdio.h>

int main()
{
    FILE *fs, *ft;
    char c[10];
    fs = fopen("source.txt", "r");
    c[0] = getc(fs);
    fseek(fs, 0, SEEK_END);
    fseek(fs, -3L, SEEK_CUR);
    fgets(c, 5, fs);
    puts(c);
    return 0;
}

#include<stdio.h>
char *str = "char *str = %c%s%c; main(){ printf(str, 34, str, 34);}";

int main()
{
    printf(str, 34, str, 34);
    return 0;
}

#include<stdio.h>

int main()
{
    printf("%%%%\n");
    return 0;
}