简单的 for 循环突然使 C 中的程序崩溃

Question

I am using MSVC via

cl file.c

with this very simple code:

#include <stdio.h>
#include <stdlib.h>
    
int
main(void) {
    
    int num = 50, pointNum = 60, max = 0;
    
    puts("Hello");

    for (int i = 0; i <= num; i++) {
        printf("%d\n", pointNum % i);
    }

    return 0;
}

but when I run it from the commandline, it just pauses and then crashes, only printing "Hello". I have no clue what is wrong, because it seems error free.

Answer 1

When i == 0 , you perform the math 60 % 0 which triggers division by zero. That triggers undefined behavior which often will crash your program.

Answer 2

In the very first iteration of the loop, the divisor is 0. But division by 0 is not possible. Thus, it simply crashes. Instead of this code snippet, I think you should use

for (int i = 1; i <= num; i++) {
    printf("%d\n", pointNum % i);
}

This will not provide any error.