gistfile1.c

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

int main() {
    int flag=0;
    char buf[20];
    char * point= (char *) &flag;
    fprintf(stderr,"How can you write on flag?\n");
    fgets(buf,20,stdin);
    fprintf(stderr,"Your input is ");
     
    fprintf(stderr,"\n");
    if(flag == -1) {
        fprintf(stderr,"Good job.\n");
        fprintf(stderr,"Your checkin key is.....");
        system("/checkin");
    }
    else {
        fprintf(stderr,"flag = %d Sorry....\n",flag);
    }
    return 0;
}