将整数或双精度数相加时的 C++ 奇怪输出

Question

我在 C++ 中将数字类型加在一起时遇到问题，无法弄清楚为什么会发生这种情况，我希望当我一起输入 3 个保龄球得分时，我会得到 9 或 9.00，而不是像 3.31748e+258 这样疯狂的东西，什么我做错了吗？任何帮助都会大有帮助，谢谢！

#include<iostream>
#include<cmath>
#include <iomanip>
#include <cstdio>   
#include <cstdlib>

using namespace std;

int main()
{
/*Coordinate variables*/
double bowlTotal;
double bowlScore;  
const int FIVE_PLAYERS = 5;

for( int players = 0; players < FIVE_PLAYERS ; players++ )
{
    cout << "Player " << players + 1 << endl << endl;

    for( int games = 0; games < 3; games++ )
    {

     double score;
     score = 0;

     cout << "Please enter score for game #" << games + 1<< ": ";
     cin >> score;
     cout << endl;

     bowlTotal += score;
    } 


     cout << endl << endl <<"The final score for player #"<< players + 1 << " = " << bowlTotal << endl << endl;
     bowlScore += bowlTotal;
}
cout << endl << endl <<"The final team score = " << bowlScore << endl << endl;

system("PAUSE");
return 0;
}

Answer 1

使用前需要先将变量初始化为0，如下图。

double bowlTotal = 0.0;
double bowlScore = 0.0;  

通常编译器不会为您执行此操作，并且变量将填充有效的垃圾值，您可以在其中添加分数。

正如 GManNickG 简洁地说的那样，reading an uninitialized variable is undefined behavior。

Answer 2

您没有初始化 bowlTotal 或 bowlScore，所以它们包含垃圾。