我如何随机选择？ [英] How I can randomly selection?

问题描述

我需要在此代码中随机选择两行，

 void init（int a [SIZE] [SIZE]，int sum [ SIZE]）
 {
 srand（time（NULL））; 
 int i，j; 
 for（i = 0; i< SIZE; ++ i）
 {
 sum [i] = 0; 
 for（j = 0; j< SIZE; ++ j）
 {
 a [i] [j] = rand（）％2; 
 sum [i] + = a [i] [j]; 
} 
} 
} 
 void dump（int a [SIZE] [SIZE]，int sum [SIZE]）
 {
 int i，j ; 
 for（i = 0; i< SIZE; ++ i）
 {
 for（j = 0; j< SIZE; ++ j）
 printf（％2d ，a [i] [j]）; 
 printf（sum =％d \ n，sum [i]）; 
} 
} 

我的尝试：



我尝试了一些代码，但我找不到我的解决方案。

解决方案

我们帮不了你，我们不知道应该做什么，更不用说你没想到或没做过的事情。



所以，它是将来取决于你。

幸运的是，你有一个工具可以帮助你找到正在发生的事情：调试器。你如何使用它取决于你的编译器系统，但是一个快速的谷歌用于你的IDE名称和调试器应该给你你需要的信息。



放一个断点在函数的第一行，并通过调试器运行代码。然后查看您的代码，并查看您的数据并找出手动应该发生的事情。然后单步执行每一行检查您预期发生的情况正是如此。如果不是，那就是当你遇到问题时，你可以回溯（或者再次运行并仔细观察）以找出原因。


对不起，但是我们不能为你做到这一点 - 时间让你学习一种新的（非常非常有用的）技能：调试！

到目前为止，我没有看到任何特别的错误。你的代码。目前还不清楚你在问什么。



如果你想随机选择那么你已经拥有了它，大部分时间。基本上，它是

  int  GetRandomValue（ int 的可能性）
 { 
 返回 rand（）％的可能性; 
} 

首先，你必须确定有多少种可能性。如果你想要一个连续的那么：

  int  possibilities = SIZE; 
 

如果你想要一个矩阵，那么：

  int 的可能性= SIZE * SIZE; 
 

如果你想要两个选择，那么得到两个随机数，并确保它们不相同：

  int  select1 = GetRandomValue（可能性）; 
  int  select2 =  0 ; 
 执行 
 {
 select2 = GetRandomValue（可能性）; 
}  while （select1 == select2）; 
 

这个循环将继续，直到选择不同。



这是你要问的还是别的？

I need randomly two row select in this code,

void init(int a[SIZE][SIZE], int sum[SIZE])
{
  srand(time(NULL));
  int i,j;
  for (i=0; i<SIZE; ++i)
  {
    sum[i] = 0;
    for(j=0; j<SIZE; ++j)
    {
      a[i][j] = rand() % 2;
      sum[i] += a[i][j];
    }
  }
}
void dump(int a[SIZE][SIZE], int sum[SIZE])
{
  int i,j;
  for (i=0; i<SIZE; ++i)
  {
    for(j=0; j<SIZE; ++j)
      printf("% 2d", a[i][j]);
    printf(" sum = %d\n", sum[i]);
  }
}

What I have tried:

I was try some codes but I can't find my solution.

解决方案

We can't help you much, we have no idea what that is supposed to do, much less what it does that you didn't expect or didn't do that you did.

So, it's going to be up to you.
Fortunately, you have a tool available to you which will help you find out what is going on: the debugger. How you use it depends on your compiler system, but a quick Google for the name of your IDE and "debugger" should give you the info you need.

Put a breakpoint on the first line in the function, and run your code through the debugger. Then look at your code, and at your data and work out what should happen manually. Then single step each line checking that what you expected to happen is exactly what did. When it isn't, that's when you have a problem, and you can back-track (or run it again and look more closely) to find out why.

Sorry, but we can't do that for you - time for you to learn a new (and very, very useful) skill: debugging!

So far, I see nothing particularly wrong with your code. It's just unclear what it is you are asking about.

If you want a random selection then you already have that, for the most part. Basically, it's

int GetRandomValue( int possibilities )
{
   return rand() % possibilities;
}

First you have to determine how many possibilities there are. If you want one out of a row then :

int possibilities = SIZE;

If you want one out of the matrix then :

int possibilities = SIZE * SIZE;

If you want two selections then get two random numbers and make sure they aren't the same :

int select1 = GetRandomValue( possibilities );
int select2 = 0;
do
{
     select2 = GetRandomValue( possibilities );
} while( select1 == select2 );

This loop will continue until the selections are different.

Is this what you are asking or is it something else?

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