#include
int mul(int a, int b);
int main(void) {
int x, y, z;
x = 10;
y = 20;
z = mul(x, y); /* 1 */
printf("%d", mul(x,y)); /* 2 */
mul(x, y); /* 3 */
return 0;
}
int mul(int a, int b) {
return a * b;
}