C++ Primer Plus 代码学习解析（第六章 6.13-6.16）

6.13 cinfish.cpp

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
const int Max = 5;
int main()
{
    using namespace std;
    // get data
    double fish[Max];
    cout << "Please enter the weights of your fish.\n";
    cout << "You may enter up to " << Max
        << " fish <q to terminate>.\n";
    cout << "fish #1: ";
    int i = 0;
    while (i < Max && cin >> fish[i]) {
        if (++i < Max)
            cout << "fish #" << i + 1 << ": ";
    }
    // calculate average
    double total = 0.0;
    for (int j = 0; j < i; j++)
        total += fish[j];
    // report results
    if (i == 0)
        cout << "No fish\n";
    else
        cout << total / i << " = average weight of "
        << i << " fish\n";
    cout << "Done.\n";
    // code to keep VC execution window open if q is entered
    //	if (!cin)  // input terminated by non-numeric response
    //	{
    //	    cin.clear();  // reset input
    //	    cin.get();    // read q
    //	}
    //	cin.get();    // read end of line after last input
    //	cin.get();    // wait for user to press <Enter>
    return 0;
}

1. 该代码演示了将一系列数字输入到数组的过程
2. while (i < Max && cin >> fish[i])首先判断&&左边的条件是否符合，避免溢出，不溢出则开始右侧表达式，将输入存到fish【】中
3. 之后for循环计算总重量
4. 最后还有if-else来判断输入是否为0，非零则正常计算（输入