Programming Language: C++

1). Given the function prototype void fun1(int &, double); is the following function call valid or invalid? Why or why not?

int x, y;

double z;

fun1(x + y, z);

2). Given the function prototype double fun2(int , double); is the following function call valid or invalid? Why or why not?

double x, y;

fun2(x, fun2(x, y));