https://stackoverflow.com/questions/35893305/factorial-program-in-c-is-wrong-after-20 Factorial program in C is wrong after 20 It works up until 20 but if 21 is entered it returns 1419745... when 21 factorial is actually 51090942171709440000. I'm assuming that this is because of the unsigned long maxing out but where does ... stackoverflow.com 이 모든것에 대한 요약..... 스택오버플로우없이 못살아 첫 번째 문제... 30!, 30 팩..