#include <stdio.h>



char * convert(int dec, char *output) {
    output[4] = '\0';
    output[3] = (dec & 1) + '0';
    output[2] = ((dec >> 1) & 1) + '0';
    output[1] = ((dec >> 2) & 1) + '0';
    output[0] = ((dec >> 3) & 1) + '0';
    return output;
}

int main(void) {
    
    char binary[5];
    convert(1, binary);
    printf("%s", binary);
    return 0;
}