http://www.jungol.co.kr/bbs/board.php?bo_table=pbank&code=2815 JUNGOL www.jungol.co.kr #include int N, cnt, R; int bin[32]; int main(void) { cnt = 31; scanf("%d", &N); while (N) { R = N % 2; N /= 2; bin[cnt--] = R; } for (int i = cnt + 1; i < 32; i++) { printf("%d", bin[i]); } return 0; }