C++ 中的二进制搜索 [已关闭]

问：

基本上，我需要了解如何在屏幕上输出值，以实现二进制搜索的成功部分。我试图更改 的初始值，但它要么崩溃，要么保持不变。我逐步浏览了代码，一切似乎都正常工作。last

编译器中的程序示例

#include<iostream>

using namespace std;

void binarySearch();

int main()
{
    //Called the function in main
    binarySearch();
    system("pause");
    return 0;
};

//void function for binary Search
void binarySearch()
{
      //creating array
      int array[100];
       array[0] = 1;
       int i,target;
      // using Boolean to create pattern for generated numbers in the array
      bool check = false;

      //loop to implement pattern
      for (int x = 1; x < 100; x++)
      {
        if (check == true)
        {
           array[x] = array[x - 1] + 1;
           check = false;
        }
        else
        {   
           array[x] = array[x - 1] + 2; 
           check = true;

        }
       }

     **Code found online and modified to fit**  

  int first,mid,last,completed,successful,tests;
  completed = 0;
  successful = 0;
  tests = 0;
  double percentage;
  percentage = 1;

  for(int x=0;x<100;x++)
  {
    // Initialize first and last variables.
    first = 0;
    last = 2;
    srand( (unsigned)time( NULL ) );      
    int target = (rand() % 150) + 1;

    while(first <= last)
    {
       mid = (first + last)/2;

       if(target > array[mid])
       {
          first = mid + 1;
          tests++;          
       }
       else if(target < array[mid])
       {
          last = mid + 1;
          tests++;
       }
       else
       {
          first = last - 1;
       }
       if(target == array[mid])
       {
          successful++;
       }
    }
    completed++;
  } 

**Area which the error occur No value for successful**
//Output on screen
cout << endl;
cout << "There were "<< completed <<" searches completed."<< endl; 
cout << "There were "<< successful <<" successful searches." << endl; 
cout << percentage <<"%"<<" of the searches were successful." << endl; 
cout << "There was an average of " << completed << " tests per search." << endl;
cout << endl;

}