Matrix Multiplication using C

int main()
{
int m, n, p, q, c, d, k, sum = 0;
int first[10][10], second[10][10], multiply[10][10];

printf("Enter number of rows and columns of first matrix\n");
scanf("%d%d", &m, &n);
printf("Enter elements of first matrix\n");

for (c = 0; c < m; c++)
for (d = 0; d < n; d++)
scanf("%d", &first[c][d]);

printf("Enter number of rows and columns of second matrix\n");
scanf("%d%d", &p, &q);

if (n != p)
printf("The matrices can't be multiplied with each other.\n");
else
{
printf("Enter elements of second matrix\n");

for (c = 0; c < p; c++)
  for (d = 0; d < q; d++)
    scanf("%d", &second[c][d]);

for (c = 0; c < m; c++) {
  for (d = 0; d < q; d++) {
    for (k = 0; k < p; k++) {
      sum = sum + first[c][k]*second[k][d];
    }

    multiply[c][d] = sum;
    sum = 0;
  }
}

printf("Product of the matrices:\n");

for (c = 0; c < m; c++) {
  for (d = 0; d < q; d++)
    printf("%d\t", multiply[c][d]);

  printf("\n");
}

}

return 0;
}