c++ primer plus 第八章《编程题8.7.4》

/*
My lady first.
10.5212   20.3333   30.2256   0
My lady first.
10.5212   20.3333   30.2256   6466.18
*/
#include <iostream>

using namespace std;

struct box {
    char maker[40];
    float height;
    float width;
    float length;
    float volume;
};

void show(const box &book);
void vol(box &book);

int main() {
    //cout.precision(8);
    //cout.setf(ios::fixed, ios::floatfield);
    box book = {"My lady first.", 10.5212, 20.3333, 30.2256};
    show(book);
    vol(book);
    show(book);

    return 0;
}

void show(const box &book) {
    cout << book.maker << "\n";
    cout << book.height << "   " << book.width << "   " << book.length << "   " << book.volume << "\n";
}

void vol(box &book) {
    book.volume = book.height * book.width * book.length;
}