rand（）在编译时生成相同的数字 [英] rand() generating same number upon compilation

问题描述

可能重复：

我一直在学习如何使用rand（）函数，我在C ++中写了一个小猜测游戏，如下所示，但问题是，无论如何很多时候我编译程序生成的数字是一样的 - > 41

  #include< iostream> 
 #include< cstdlib> 
 #include< conio.h> 
 using namespace std; 
 
 int main（）
 {
 int x = rand（）％100; 
 int y = 0; 
 cout<< Ghiceste numarul！ << endl; 
 cin>> y; 
 
 while（y！= x）{
 
 if（y> x）{
 cout< Numarul tau este prea mare！Incearca un numar mai mic！ << endl; 
 cin>> y; 
} 
 
 if（y< x）{
 cout< Numarul tau este prea mic！ << endl; 
 cin>> y; 
} 
 
 if（y == x）{
 cout< FELICITARI，AI GHICIT NUMARUL！\\\
; 
 return 0; 
} 
} 
} 
  

max的rand（），它的确改变了，只要我把它< 41。

有什么想法吗？我没有一个线索为什么会发生这种情况。我使用CodeBlocks IDE并尝试重建（CTRL + F11）

解决方案

尝试添加

  srand（time（0））;  main 开头处的
  

Possible Duplicate:
What's the Right Way to use the rand() Function in C++?

I've been learning how to use the rand() function and I wrote a small guessing game in C++ as seen bellow, but the problem is, no matter how many times I compile the programs the generated number is the same -> 41

#include <iostream>
#include <cstdlib>
#include <conio.h>
using namespace std;

int main()
{
    int x = rand()%100;
    int y=0;
    cout << "Ghiceste numarul!" << endl;
    cin >> y;

    while(y != x) {

         if(y > x) {
            cout << "Numarul tau este prea mare! Incearca un numar mai mic!" << endl;
            cin >> y;
          }

             if(y < x) {
                 cout << "Numarul tau este prea mic!" << endl;
                 cin >> y;
               }

      if (y == x) {
      cout << "FELICITARI, AI GHICIT NUMARUL!\n";
      return 0;
      }
    }
}

I also tried to change the max value of rand() and it did change as long as I put it < 41.

Any ideas? I don't have a clue as to why this is happening. I am using CodeBlocks IDE and I tried rebuilding (CTRL+F11)

解决方案

Try adding

srand(time(0));

at the beginning of main.

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