why is line 34 adding a huge number?
#include <stdio.h>
int populate_array(int, int *);
int check_sin(int *);

int main() {
    int sin_array[9]; 
    int sin = 820320726;
    populate_array(sin, sin_array);
    check_sin(sin_array);
}

int populate_array(int sin, int *sin_array) {
    int digits = 0;
    int num = sin;
    while (num > 0) {
        sin_array[9 - digits] = num % 10;
        num = num / 10;
        digits++;
    }
    if (digits != 9) {
        return 1;
    }
    return 0;
}

int check_sin(int *sin_array) {
    int sum = 0;
    for (int i = 0; i < 9; i++) {
        if (i % 2 == 1) {
            sin_array[i] *= 2;
        }
        if (sin_array[i] >= 10) {
            sum += (sin_array[i] % 10);
            sum += (sin_array[i] / 10);
        }
        else {
            sum += sin_array[i];
        }
    }
    if (sum % 10 == 0) {
        return 0;
    }
    return 1;
}