【C++】引用作为函数形参的练习

#include <iostream>

using namespace std;

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

void set_pc(free_throws &ft);
void display(const free_throws &ft);
free_throws & accumlate(free_throws &target,const free_throws &source);
int main()
{
    free_throws one = {"Rick",13,14};
    free_throws two = {"jack",10,16};
    free_throws three = {"Rose",11,13};
    free_throws four = {"Mike",12,17};
    free_throws team = {"Class 6",0,0};
    set_pc(one);
    display(one);
    accumlate(accumlate(accumlate(accumlate(team,one),two),three),four);
    display(team);
    return 0;
}

void set_pc(free_throws &ft)
{
    if(ft.attempts != 0)
        ft.percent = 100.0 * float(ft.made) / float(ft.attempts);
    else
        ft.attempts = 0;
}

void display(const free_throws &ft)
{
    cout << "Name: " << ft.name << endl;
    cout << "Made: " << ft.made << "\t";
    cout << "Attempt: " << ft.attempts << "\t";
    cout << "Percent: " << ft.percent << endl;
}

free_throws & accumlate(free_throws &target,const free_throws &source)
{
    target.attempts += source.attempts;
    target.made += source.made;
    set_pc(target);
    return target;
}