#include <iostream>
 
void square_ref(int& a);
int  square_val(int a);
 
int main() {
	int a = 2;
	int s = 2;
 
	std::cout << "a: " << a << ", s: " << s << std::endl;
	std::cout << "------" << std::endl;
 
	square_ref(a);
	square_val(s);
	std::cout << "a: " << a << ", s: " << s << std::endl;
	std::cout << "------" << std::endl;
 
	square_ref(a);
	s = square_val(s);
	std::cout << "a: " << a << ", s: " << s << std::endl;
 
	return 0;
}
 
void square_ref(int& a)
{
	a = a*a;
}
 
int square_val(int a)
{
	return a*a;
}

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