函数：按引用传递函数参数进行操作

#include <iostream>
#include <string>

struct free_throws
{
	std::string name;
	int made;
	int attempts;
	float percent;
};

void display(const free_throws & ft);
void set_pc(free_throws & ft);
free_throws & accumulate(free_throws & target, const free_throws & source);

int main(void)
{
	using std::cout;
	free_throws one = {"Ifelsa Branch", 13, 14};
	free_throws two = {"Andor Knott", 10, 16};
	free_throws three = {"Minnie Max", 7, 9};
	free_throws four = {"Whily Looper", 5, 9};
	free_throws five = {"Long Long", 6, 14};
	free_throws team = {"Throwgoods", 0, 0};
	
	free_throws dup;
	
	set_pc(one);
	display(one);
	accumulate(team, one);
	display(team);
	
	display(accumulate(team, two));
	accumulate(accumulate(team, three), four);
	display(team);
	
	dup = accumulate(team, five);
	
	cout << "Displaying team:\n";
	display(team);
	cout << "Displaying dup after assignment:\n";
	display(dup);
	set_pc(four);
	
	accumulate(dup, five) = four;
	cout << "Displaying dup after ill-advised assignment:\n";
	display(dup);
	return 0;
}
void display(const free_throws & ft)
{
	using std::cout;
	cout << "Name: " << ft.name << '\n';
	cout << " Made: " << ft.made << '\t';
	cout << "Attempts: " << ft.attempts << '\t';
	cout << "Percent: " << ft.percent << '\n';
}
void set_pc(free_throws & ft)
{
	if(ft.attempts != 0)
		ft.percent =100.0f * float(ft.made)/float(ft.attempts);
	else
		ft.percent = 0;
}
free_throws & accumulate(free_throws & target, const free_throws & source)
{
	target.attempts += source.attempts;
	target.made += source.made;
	set_pc(target);
	return target;
}