棒球击球平均项目

Question

我需要一个帮助学校的项目。我们必须编写一个程序，向用户询问关于棒球运动员的信息。我们需要计算玩家的击球平均数，击球次数和命中次数。我遇到了一个问题，即我的平均计算结果是输出一个集合数并且没有执行任何计算。我输入用于计算的所有变量的整数。所以我会输入数字如1，4，10等......由于该程序的价值，我的公式设置自己等于15903.876。我用于平均公式的所有变量均被声明为整数，而击球平均本身被声明为双精度。我已经做了一些自我调试，并发现当它将蝙蝠的次数除以命中次数时，计算会产生混乱。如果有人能帮我弄清楚这个问题，我会很感激。

//libaries 
#include <iostream> 
#include <string> 
#include <sstream> 
#include <iomanip> 
using namespace std; 

class battingAverage 
{ 
public: 

    string pName; 
    int nBats; 
    int tHits; 
    int gPlayed; 
    int gcalled; 
    double average; 
    double average1; 
    double playeraverage; 

}; 

int main() 
{ 
    string numberPlayers; 
    int nplayers; 
//enters the number of players the user wants to enter data for 
cout << "Enter the number of players you want to enter data for: "; 
cin >> numberPlayers; 
cout << endl; 

//converts the value of numberPlayers to nplayers 
istringstream convert(numberPlayers); 

//sets integer nplayers equal to the value of the string numberPlayers 
if(! (istringstream(numberPlayers) >> nplayers)) 
{ 
    nplayers = 0; 
} 

cout << "This program calculates the batting average of baseball players.\nYou may enter data for " << nplayers << " players." << endl; 

battingAverage ba[nplayers]; 

int index = 0; 

//while statement to get data 
while(index < nplayers) 
{ 
    cout << "Enter the players last name: " << endl; 
    cin >> ba[index].pName; 

    cout << "Enter the number of games the player played: " << endl; 
    cin >> ba[index].gPlayed; 
    cout << ba[index].gPlayed << endl; 

    cout << "Enter the number of games the player was called in for: " << endl; 
    cin >> ba[index].gcalled; 
    cout << ba[index].gcalled << endl; 

    cout << "Enter the number of times the player was at bat: " << endl; 
    cin >> ba[index].nBats; 
    cout << ba[index].nBats << endl; 

    cout << "Enter the number of time the player hit: " << endl; 
    cin >> ba[index].tHits; 
    cout << ba[index].tHits << endl; 

    if(ba[index].tHits > ba[index].nBats) 
    { 
    cout << "Enter a valid value for the number of times the player hit: "; 
    cin >> ba[index].tHits; 
    } 

    cout << endl; 
    index++; 

} 

//rounds average to 3 decimal places 
cout << fixed << setprecision(3); 
//average formula 
ba[index].playeraverage = (ba[index].nBats/ba[index].tHits) * (ba[index].gPlayed/ba[index].gcalled);//error 
cout << ba[index].playeraverage << endl << endl;//just temp line to check calculation of average. 

ba[index].average = .000; 
ba[index].average1 = .099; 

while(ba[index].average < 1 && ba[index].average1 < .899) 
{ 
    ba[index].average +=.100; 
    ba[index].average1 += .1; 
    //prints chart 
    cout << setprecision(1) << ba[index].average << "00" << setprecision(3) << setw(12) << ba[index].average1 << endl; 
    } 

cout << "1.000" << setw(12) << "1.000" << endl; 

//version of system pause 
cout << "\nPress enter to continue..."; 
cin.sync(); 
cin.ignore(); 
return 0; 

}

Answer 1

在计算过程中，您的索引值是错误的。

我马上发现这是我把你的代码在调试器，并通过它加强，有些东西你真的应该做自己。

您从int index = 0;开始，并在用户输入每个玩家的数据时增加它。 在输入循环结束时，索引现在与玩家数量相同。
（例如，如果你有5名球员，指数目前是5，玩家的数据存储在ba[0]，ba[1]，ba[2]，ba[3]和ba[4]）

注意，在这一点上ba[5]是不有效的数据。但那正是ba[index]！

你对ba[index]做了所有的计算，这是无效的数据，你想知道为什么你会得到毫无意义的结果？

我建议你在开始计算之前将索引设置回0，然后再做一个循环，为每个玩家进行必要的计算0 ... 4。

Answer 2

在此行中：因为这两个nBats和tHits是整数，您只使用整数运算

(ba[index].nBats/ba[index].tHits) 

：

ba[index].playeraverage = (ba[index].nBats/ba[index].tHits) * (ba[index].gPlayed/ba[index].gcalled);//error 

你有这样的表达。
答案将是一个整数。

例如：
nBats = 10 & tHits = 3，你所期望的表达是3.333。再以约gPlayed和gcalled表达

((double)ba[index].nBats/ba[index].tHits) 

同一件事：
，但只会是3

为了解决这个问题，我建议改变来。