I ran into this issue in a bigger program I was making, so I tried to boil down the issue to a lot less code.

The issue is that I have a while loop, that runs and takes some user input, and then terminates or keeps running based on the input of the user. My example looks like this:

int main() {

    int running = 0;

    while (running == 0){

        int n;
        fflush(stdin);

        scanf("%d", n);
        printf("n is %d \n", n);


    if (n == 0){
        running =1;
    }
    }
}

And whatever input I give, this fails in the following way:

Process finished with exit code 139 (interrupted by signal 11: SIGSEGV)

I understand that this problem often happens when you mess up some memory adresses or some pointers. But I really can't see what's going wrong here though, I only have two variables, and I'm deleting anything.

Can someone help me

CodePudding user response：

Two errors in 2 lines.

1. Major: scanf("%d", n); scanf requires pointer you pass integer. Undefined behaviour
2. fflush(stdin); - it is UB (Undefined Behaviour) too