Can somebody explain to me how this works/help me trace the output please?

#include using namespace std;

int s=1, y=3;

void confuse1(int &y, int s) {

s++;

y++;

}

void confuse2(int b, int *s) {

y = ++(*s);

*s = b;

} void confuse3(int &a, int *s) {

a = *s + 1; (*s)++;

}

int main() {

int s=2;

confuse1( s, y);

confuse2( s, &y);

confuse3( s, &y);

printf("s + y = %d ", s+y);

return 0;

}