Question

我是c ++的新手，我正在尝试完成我的第一个任务。我不需要决定，但我想知道我做错了什么？这是我的代码：

#include <iostream>
using namespace std;

int main(){

    int chTenders;
    int frOrders;
    int macCh;
    int drinks;
    int sauces;
    float tip;
    float subtotal;
    subtotal = chTenders + frOrders + macCh + drinks + sauces + tip;

    cout << "How many chicken tenders would you like?\n";
    cin >> chTenders;
    cout << "How many orders of fries would you like?\n";
    cin >> frOrders;
    cout << "How many orders of mac and cheese would you like?\n";
    cin >> macCh;
    cout << "How many drinks would you like?\n";
    cin >> drinks;
    cout << "How many sauces would you like?\n";
    cin >> sauces;
    cout << "How much would you like to tip?\n";
    cin >> tip;

    cout << "====Slim's Order====\n";
    cout << "Subtotal $" << subtotal << endl;


    return 0;
        }

当我编译并运行它时，它给了我$ 2.60929e + 08而不是6.0：

How many chicken tenders would you like?
1
How many orders of fries would you like?
1
How many orders of mac and cheese would you like?
1
How many drinks would you like?
1
How many sauces would you like?
1
How much would you like to tip?
1
====Slim's Order====
Subtotal $2.60929e+08

Answer 1

我认为您的计算顺序刚刚结束。 subtotal是在您将输入值接收到被加数（chTenders，frOrders等）之前计算出来的。将subtotal=...行移至cin << tip语句之后。

Answer 2

要详细说明原因，您要在之前中计算小计的值，然后将所有值分配给变量。在C ++中，在为变量分配值之前，对其进行访问的结果基于某个其他进程曾经写入该位内存的内容。因此，您实际上计算了一个垃圾值，然后要求用户输入。在C ++中，在定义变量的同时初始化变量通常被认为是一种好习惯。

为什么int plus float给我显示奇怪的数字？

2 个答案: