xxxxxxxxxx
// one way to solve it is to declare your function before the main
//sample
//Here I declated the fuction before the main
void interchange(int x, int y);
int main(){
int x = 8, y = 13;
interchange(x, y);
return 0;
}
void interchange(int x, int y){
int z;
x = z;
x = y;
y = z;
}