警告C4244：'argument'：从'time_t'转换为'unsigned int'，可能丢失数据 - C ++ [英] warning C4244: 'argument' : conversion from 'time_t' to 'unsigned int', possible loss of data -- C++

问题描述

我做了一个简单的程序，允许用户选择一些骰子，然后猜测结果...我发布此代码之前，但与错误的问题，所以它被删除...现在我不能有任何错误，甚至警告C4244：'参数'：从'time_t'到'unsigned int'的转换，但是由于某些原因，这个警告持续弹出，我不知道如何解决它...
可能会丢失数据

I made a simple program that allows the user to pick a number of dice then guess the outcome... I posted this code before but with the wrong question so it was deleted... now I cannot have any errors or even warnings on this code but for some reason this warning keeps popping and I have no clue how to fix it... "warning C4244: 'argument' : conversion from 'time_t' to 'unsigned int', possible loss of data"

#include <iostream>
#include <string>
#include <cstdlib>
#include <time.h>

using namespace std;

int  choice, dice, random;

int main(){
    string decision;
    srand ( time(NULL) );
    while(decision != "no" || decision != "No")
    {
        std::cout << "how many dice would you like to use? ";
        std::cin >> dice;
        std::cout << "guess what number was thrown: ";
        std::cin >> choice;
         for(int i=0; i<dice;i++){
            random = rand() % 6 + 1;
         }
        if( choice == random){
            std::cout << "Congratulations, you got it right! \n";
            std::cout << "Want to try again?(Yes/No) ";
            std::cin >> decision;
        } else{
            std::cout << "Sorry, the number was " << random << "... better luck next  time \n" ;
            std::cout << "Want to try again?(Yes/No) ";
            std::cin >> decision;
        }

    }
    std::cout << "Press ENTER to continue...";
    std::cin.ignore( std::numeric_limits<std::streamsize>::max(), '\n' );
    return 0;
}

这是我想要弄清楚的，为什么我收到此警告：
警告C4244：'argument'：从'time_t'转换为'unsigned int'，可能丢失数据

This is what I am trying to figure out, why am I getting this warning: warning C4244: 'argument' : conversion from 'time_t' to 'unsigned int', possible loss of data

推荐答案

p>这是因为在你的系统上， time_t 是比 unsigned int 更大的整数类型。

That's because on your system, time_t is a larger integer type than unsigned int.

• time（）返回 time_t 可能是64位整数。


• srand（）想要一个 unsigned int 这可能是一个32位整数。

• time() returns a time_t which is probably a 64-bit integer.
• srand() wants an unsigned int which is probably a 32-bit integer.

因此您会收到警告。您可以使用转换将其静音：

Hence you get the warning. You can silence it with a cast:

srand ( (unsigned int)time(NULL) );

在这种情况下，下转（和潜在的数据丢失）使用它种子RNG。

In this case, the downcast (and potential data loss) doesn't matter since you're only using it to seed the RNG.

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