在Dev C ++上編譯相同的代碼，但在Visual Studio 2017上編譯

Question

#include<cstdlib>           //Required for compatibility
#include<cmath>             //Required for pow
#include<fstream>           //Required for data files
#include<iostream>          //Required for cout and cin
#include<iomanip>           //Required for setw

using namespace std;

int choice, loops, count;
double initTime, timeIncrement, finalTime, time, A1, B1, C1, D1, E1, 
altitude, A2, B2, C2, D2, E2, velocity;         //This is line 20 as the error notes            
//Declare variables
ifstream inFile;
ofstream outFile;


void menuFunction() {                                                                               
//Main menu function where user selects which option they would like to proceed with, not relevant to question
}

double altitudeFunction(double& altitude) {                                                                         
//Altitude calculation
     altitude = A1 * pow(time, 4.0) + B1 * pow(time, 3.0) + C1 * pow(time, 2.0) + D1 * time + E1; //This is line 36 as the error notes
}

double velocityFunction(double& velocity) {                                                                         
//Velocity calculation
     velocity = A2 * pow(time, 4.0) + B2 * pow(time, 3.0) + C2 * pow(time, 2.0) + D1 * time + E1; // This is line 41, as the error notes
}

void parameters() {                                                                     
//Function to enter time parameters to save space, not relevant to errors      
}

int main() {
    menuFunction();

    while (choice != 4) {
        switch (choice) {

        case 1: {
            parameters();
            if (finalTime < 5 || finalTime > 24) {                                  
 //Required invalid entry error message                                             
//Redisplay menu to allow user another try
            }
            else {
               //Open input file for option 1
               //Find variables in input file
               //close input file and open output file                                                      
              //Make output file look neat
            //Column headers for output file for readability
                loops = (int)((finalTime - initTime) / timeIncrement);
                for (count = 0; count <= loops; count++) {                                      //For loop for incremental calculations, this is line 86 as the error notes
                time = initTime + count * timeIncrement;                                                                
                 //Run both calculation functions
                 //Print results to output file during for loop
            }
            //close output file
            system("CLS");
            //Print message to screen saying data was recorded to output file
        }
        break;
    }

    case 2: {
        parameters();
            if (finalTime < 5 || finalTime > 24) {                                  
 //Required invalid entry error message                                             
//Redisplay menu to allow user another try
            }
            else {
               //Open input file for option 1
               //Find variables in input file
               //close input file and open output file                                                      
              //Make output file look neat
            //Column headers for output file for readability
                loops = (int)((finalTime - initTime) / timeIncrement);
                for (count = 0; count <= loops; count++) {                                      //For loop for incremental calculations, this is line 118 as the error notes
                time = initTime + count * timeIncrement;                                                                
                 //Run both calculation functions
                 //Print results to output file during for loop
            }
            //close output file
            system("CLS");
            //Print message to screen saying data was recorded to output file
        }
        break;
    }

    case 3: {
    parameters();
            if (finalTime < 5 || finalTime > 24) {                                  
 //Required invalid entry error message                                             
//Redisplay menu to allow user another try
            }
            else {
               //Open input file for option 1
               //Find variables in input file
               //close input file and open output file                                                      
              //Make output file look neat
            //Column headers for output file for readability
                loops = (int)((finalTime - initTime) / timeIncrement);
                for (count = 0; count <= loops; count++) {                                      //For loop for incremental calculations, this is line 150 as the error notes
                time = initTime + count * timeIncrement;                                                                
                 //Run both calculation functions
                 //Print results to output file during for loop
            }
            //close output file
            system("CLS");
            //Print message to screen saying data was recorded to output file
        }
        break;
    }

    default: {
        cout << "\tInvalid Entry!\n\n";                                     //Error message if user enters an invalid menu option
        menuFunction();
    }
    }
}

    if (choice == 4) {
       //end program
        system("pause");
        return 0;
    }
}

在我使用C ++編碼的第一學期中，我不明白為什么，但是由於某種原因，當我運行此確切的程序時，它在Dev C ++中可以正常編譯，但是在Visual Studio 2017中出現了很多錯誤。我試圖復制並粘貼錯誤，但格式不正確，因此基本上每個'time'和'count'實例都給我一個錯誤，指出“'time / count'不明確”以及以下較不常見的錯誤：

錯誤C2659'='：用作左操作數86、118、150

錯誤C2365“時間”：重新定義：先前的定義是“功能” 20

錯誤C2297'*'：非法，右操作數的類型為'time_t（__cdecl *）（time_t * const）'36，41

錯誤C2665'pow'：6個重載均不能轉換所有參數類型36、41

該程序應該從輸入文件中提取氣象氣球數據輸入，進行一些數學運算以獲取特定時間的高度和速度值，並將這些值輸出到新的數據文件中。 它可以在Dev C ++上編譯，運行和完美運行，但不能在Visual Studio上編譯。 我之所以這么問，是因為我提交了這門課程，並給了0，因為它不能在教授的計算機上編譯，但在我的計算機上可以正常工作。 有任何想法嗎？

編輯后刪除了我的名字以及代碼中不相關的部分。 在代碼中用注釋替換的所有內容都可以正常工作，保留了包含錯誤的代碼部分。

Answer 1

這可能表明using namespace std;原因之一using namespace std; 是個壞主意。

標准庫包含一個std::time函數，該函數由using 。

現在，編譯器不知道普通time意味着在此程序或std::time函數中聲明的::time變量。

它可能在某些系統上編譯的原因是允許C ++標准標頭間接包含任何其他標准標頭。 因此，可能偶然地與Dev-C ++一起使用的標准庫頭文件不包含std::time 。