Calculate GCD of two number using loop

GCD.c

#include <stdio.h>
//Anan5a<https://github.com/Anan5a>
int main()
{
	int db[1000], da[1000], i, j=1, k, gcd[300], big_da, big_db;

	int num, num2;

	printf("Enter two numbers: ");
	scanf("%d %d", &num, &num2);

	for(i=1;i<=num;i++){
         if(num%i == 0){
            db[j] = i;
            j++;
        }
	}
    db[0] = j;//set max iteration
    j = 1;
    for(i=1;i<=num2;i++){
         if(num2%i == 0){
            da[j] = i;
            j++;
        }
	}
    da[0] = j;//set max iteration
    j = 1;


    //gcd[1] = da[0];

    for(i=1;i<da[0];i++){
        for(k=1;k<db[0];k++){
            if(da[i] == db[k]){
                gcd[j] = da[i];
                j++;
            }
        }
    }

    gcd[0] = j;

    big_da = gcd[1];

    for(i=1;i<gcd[0];i++){
        if(gcd[i] > big_da){
            big_da = gcd[i];
        }
    }

    big_db = db[1];

    for(i=1;i<db[0];i++){
        if(db[i] > big_db){
            big_db = db[i];
        }
    }

    printf("%d", big_da);
	return 0;
}