In C: negative numbers insertion sort

Question

I'm fairly new into programming and my teacher want me to implement insertion sort in C.

My code works, but not with negative numbers if I use it with negative numbers in my array I always get a segmentation fault:

void insertion_sort(int array[], int len) {
    int i       = 0;
    int j       = 1;
    signed int tmp     = array[0];

    for(i = 1; i < len; i++) {
        tmp = array[i];
        j = i - 1;

        if(j >= 0){
            while(tmp < array[j]) {
                array[j + 1] = array[j];
                j = j - 1;
            }
        }
      array[j + 1] = tmp;
    }
}

Answer 1

Change this code snippet

    if(j >= 0){
        while(tmp < array[j]) {
            array[j + 1] = array[j];
            j = j - 1;
        }
    }

to

    while ( j >= 0 && tmp < array[j] ) {
            array[j + 1] = array[j];
            j = j - 1;
    }

Take into account that there is no sense to initialize defined variables

int i       = 0;
int j       = 1;
signed int tmp     = array[0];

because they are overwritten in the followed statements.