在C ++中的文本文件中保存多个输出

Question

还在努力学习c++。我们的教授希望我们制作一个程序，其中温度的输出将保存在一个文本文件中。变量结果是我想要保存的输出。尽管代码有效并保存了结果，但问题是它只保存了第一个结果。我已经设置了一个限制，现在我只想保存至少 5 个结果。

#include <iostream>
#include <stdlib.h>
#include <fstream>

using namespace std;

int main()
{

   double value, the_result, result;
   int choice;

   ofstream file;
   file.open("output.txt");


   do {

        cout <<"\n\nChoose among the following:"
            "\n1 = Celsius to Fahrenheit"
            "\n2 = Celsius to Kelvin"
            "\n3 = Fahrenheit to Celsius"
            "\n4 = Fahrenheit to Kelvin"
            "\n5 = Kelvin to Celsius"
            "\n6 = Kelvin to Fahrenheit"
            "\n7 = Exit"
            "\n\nChoice:\n";
        cin >> choice;


        switch (choice){

        case 1:
            cout<<"Enter Value"<< endl;
            if (!(cin >> value )){
                cout << "Invalid Input. Please Try Again!!";
                cin.clear();
                cin.ignore(123, '\n');
            }else{
            result = value*9/5+32;
            cout <<"The result is ~"<< result << "0";
            }
            break;

        case 2:
            cout<<"Enter Value"<< endl;
            if (!(cin >> value )){
                cout << "Invalid Input. Please Try Again!!";
                cin.clear();
                cin.ignore(123, '\n');
            }else{
            result = value+273.15;
            cout <<"The result is ~"<< result << "K";
            }
            break;

        case 3:
            cout<<"Enter Value"<< endl;
            if (!(cin >> value )){
                cout << "Invalid Input. Please Try Again!!";
                cin.clear();
                cin.ignore(123, '\n');
            }else{
            the_result = value-32;
            result = the_result*5/9;
            cout <<"The result is ~"<< result << "0" << "F";
            }
            break;

        case 4:
            cout<<"Enter Value"<< endl;
            if (!(cin >> value )){
                cout << "Invalid Input. Please Try Again!!";
                cin.clear();
                cin.ignore(123, '\n');
            }else{
            the_result = value + 459.67;
            result = the_result*5/9;
            cout <<"The result is ~"<< result << "K";
            }
            break;

        case 5:
            cout<<"Enter Value"<< endl;
            if (!(cin >> value )){
                cout << "Invalid Input. Please Try Again!!";
                cin.clear();
                cin.ignore(123, '\n');
            }else{
            result = value - 273.15;
            cout <<"The result is ~"<< result << "0";
            }
            break;

        case 6:
            cout<<"Enter Value"<< endl;
            if (!(cin >> value )){
                cout << "Invalid Input. Please Try Again!!";
                cin.clear();
                cin.ignore(123, '\n');
            }else{
            result = value*9/5-459.67;
            cout <<"The result is ~"<< result << "0" << "F";
            }
            break;

        case 7:
            return EXIT_SUCCESS;
            break;


        }


        for (double i=0; i<5; i++){
            file << result<< endl;
        }
        file.close();
   }
   while (choice !=7);
}

Answer 1

只是为了扩展 AProgrammer 的评论 - 问题是在第一次迭代之后，您试图写入一个您已经关闭但没有重新打开的文件。因此，按照建议，您应该将 file.close() 移到 do while 循环之外

在C ++中的文本文件中保存多个输出

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