Program to find Greatest Common Divisor (GCD) of given two integers.

int DivisorN[100];
int DivisorM[100];
int index1, index2;
int N, M;

void findDivisorOfN()
{
    int i;
    for(i = 1; i<=N/2; i++)
{
        if(N%i == 0) {
           DivisorN[index1++] = i;
        }
    }
    DivisorN[index1++] = N;
}


void findDivisorOfM()
{
    int i;
    for(i = 1; i<=M/2; i++)
{
        if(M%i == 0) {
           DivisorM[index2++] = i;
        }
    }
    DivisorM[index2++] = M;   
}

int findGreatestCommonDivisor()
{  // Find the height Common divisor between N and M
    int i, j;
    for(i = index1-1; i>=0; i--)
{
        for(j = index2-1; j>=0; j--)
{
            if(DivisorN[i] == DivisorM[j]) 
{
                return  DivisorN[i];
            }
        }
    }

}

int main()
{
    scanf("%d %d",&N,&M);
    findDivisorOfN();
    findDivisorOfM();
    printf("%d\n",findGreatestCommonDivisor());
    return 0;
}