c++ - 除法答案未正确执行

Question

我在使用以下代码行时遇到了问题:

double answer;
answer = num[count] / den[count]
cout << " Fraction" << count + 1 << " " << num[count] 
     << " / " << den[count] << " = " << answer << endl;

为什么我的回答没有效果？我忽略了什么吗？我正在使用数组并从单独的文本文件中获取数据。当我使用上面的代码时，我得到了要正确划分的数字，但答案不正确。结果是一个随机数，通常为 0 或 1。

这是我的代码:

#include <iostream>
#include <fstream>
#include <iomanip>
#include <cstdlib>

using namespace std;
void read_data(int num[], int den[], int size);
void showValues(int num[],int den[], int size);

int main()
{
    const int size1 = 12;
    const int size2 = 12;
    ifstream dataIn;
    int num[12];
    int den[12];

    read_data(num,den,size1);
    cout << "Here are the fractions: " << endl;
    showValues(num,den,size1);

    system("PAUSE");
    return 0;
}

void read_data(int num[], int den[], int size)
{
    ifstream dataIn;
    dataIn.open("walrus.txt");

    if( dataIn.fail() )
         {
        cout << "File does not exist." << endl;
        exit(1);
         }

     int count;
     for ( count = 0; count < size; count++ )
     {
         dataIn >> num[count];
     }

     for (count = 0; count < size; count++)
     {
         dataIn >> den[count];
     }


     dataIn.close();
 }

void showValues(int num[],int den[], int size)
{
    int count;
        for (count = 0; count < size; count++)
        {
            if (den[count] == 0)
            {
                 cout << " Fraction" << count + 1 << " " 
                      << num[count] << " /" << den[count] 
                      << " Is invalid" << endl;
             }
            else
            {
                double answer;
                answer = num[count] / den[count];
             cout << " Fraction" << count + 1 << " " 
                  << num[count] << " / " << den[count] 
                  << " = " << answer << endl;
             }
        }
 }

Answer 1

@main ifstream dataIn;你没有使用这个对象

@函数读取数据:

 int count;
 for ( count = 0; count < size; count++ )
 {
     dataIn >> num[count];
 }

 for (count = 0; count < size; count++)
 {
     dataIn >> den[count];
 }

假设你的文件看起来像:

1 2 23 32 44 // numerators
2 3 1 99 24 // den

正确的阅读方式是:

int count = 0;
while( count < size && dataIn >> num[count++] ) // numerators
    ;

count = 0;
while( count < size && dataIn >> den[count++] )
    ;

@function 显示值:尝试改变

   double answer;
    answer = num[count] / den[count];
 cout << " Fraction" << count + 1 << " " 
      << num[count] << " / " << den[count] 
      << " = " << answer << endl;

到:

double answer = static_cast<double>(num[count]) / den[count];
cout << " Fraction" << count + 1 << " " 
     << num[count] << " / " << den[count] << " = " << answer << endl;