for (i = 0; i < N; i++)
for (j = 0; j < N; j++)
for (k = 0; k < N; k++)
c[i][j] += a[i][k] * b[k][j];

printf("matrix A and B \n");
for (i = 0; i < N; i++) {
for (j = 0; j < N; j++) printf("%5f ", a[i][j]);
printf("\t");
for (j = 0; j < N; j++) printf("%5f ", b[i][j]);
printf("\n");
}

printf("output C=A*B \n");
for (i = 0; i < N; i++) {
for (j = 0; j < N; j++) printf("%5f ", c[i][j]);
printf("\n");
}
return 0;
}