当输入新变量时，C++ For-Loop会卡住

Question

我是C++的新手，并试图为大学项目创建一个彩票游戏。

我有一个for循环来检查输入数组中没有重复的数字。当你拿出代码段来产生随机数时，这种方法非常好。

只要我将随机数部分添加回来，for循环就会卡住。它会不断告诉我，当它试图存储第一个号码时，我已经输入了该号码。

我附上了我所有的代码，如果你不需要这些，请致歉。

#include <iostream> 
#include <stdio.h> 
#include <time.h> 
#include <stdlib.h> 

using namespace std; 
//int loto[6]; 
int main() 
{ 
int numbers[6]; 
//void rand_num(int loto[6], int count); 
int loto[6]; //used to store the loto numbers 
//int james = 0; 
//int l,j; //used in checking any duplicated 

    srand(time(0)); 

     for(int count=0; count<6; count++) 
      { 
      loto[count] = (rand()%49)+1; 

      cout << loto[count] << endl; 
      } 



//declares the variable i to increase each time a number is entered. 
//this will only go as high as 6 
for(int i=0;i<6;i++) 
{ 
    cout<<" " << i<<" : Please enter your lottery numbers: "<<endl; 
    cin>>numbers[i]; 
     if ((numbers[i] >= 50) | (numbers[i] == 0)) 
     do 
     { 
      { 
      //checks to see if the first number entered is above 50 or = to 0 and rejects it 
      cout << "The Number must be between 1-49, please select again. " << endl; 
      cin >> numbers[i]; 
      } 
     } 
     while ((numbers[i] >= 50) | (numbers[i] == 0)); 

//---------------------------------------------------------------------------- 

//this section of code is a loop within a loop to check the number entered against all numbers already stored. 
//makes l the same as i effectively 
for(int l=0;l<6;l++) 
{ 
    //makes j one more than l 
    for(int j=l+1;j<7;j++) 
    { 
    if(numbers[l] == numbers[j]) 
     do 
     { 
      { 
      cout << "Number has already been chosen, please re-enter number " << endl; 
      cout << endl; 
      cin >>numbers[i]; 
       //checks the number that is re-entered is not <50 or = 0 
       //if so it rejects it and asks for another as above. 
       if ((numbers[i] >= 50) | (numbers[i] == 0)) 
        do 
        { 
         { 
         cout << "The Number must be between 1-49, please select again. " << endl; 
         cin >> numbers[i]; 
         } 
        } 
        while ((numbers[i] >= 50) | (numbers[i] == 0)); 
      } 
     } 
     while (numbers[l] == numbers[j]); 
    } 
} 
} 

//---------------------------------------------------------------------------- 

//this displays the numbers that have been chosen. 
cout << "Your Numbers are: " << endl; 
for (int i = 0; i<6; i++) 
{ 
    cout << " " << numbers[i]; 
} 

return 0; 
} 

Answer 1

我不确定这是真正的问题，但它是一个错误。尝试纠正它，看看它是否有帮助。

for(int l=0;l<6;l++) 
{ 
    //makes j one more than l 
    for(int j=l+1;j<7;j++) 
    { 
     if(numbers[l] == numbers[j]) 

内循环将达到j == 6，因此您将访问数组之外​​。外环应该有5个作为极限，而内环应该有6个作为极限。

编辑： 在查看了一下你的代码后，我可以看到你正在使用数字[]而没有初始化它。两个嵌套for循环将比较数字中的所有元素。但是，如果用户只输入了2个数字，其余的就会被单元化并可能导致意想不到的结果。

此外 - 你不需要每次都检查所有元素。只需检查新输入的号码（由i指数）和以前的所有号码。

最后你可能会需要这样的东西：

if (!(cin >> numbers[i])) { 
    cout << "Please enter numbers only." << endl; 
    cin.clear(); 
    cin.ignore(10000,'\n'); 
} 

处理的输入不是整数，例如“text”

对于次要的事情：

您还应该检查负数。

您正在用途|而不是||。它会正常工作，但||似乎更正确，因为它是逻辑OR（while |是一个二进制OR）。