在排序數組中的二進制搜索

Question

嗨，我想通過使用用戶通過文本框的輸入在排序的數組中進行二進制搜索。

這是我的代碼：

using System; 
using System.Collections.Generic; 
using System.ComponentModel; 
using System.Data; 
using System.Drawing; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 
using System.Windows.Forms; 

namespace arra3 { 
    public partial class Form1 : Form 
    { 
     public Form1() 
     { 
      InitializeComponent(); 
     } 

     int[] arr = { 0, 10, 20, 30, 40, 50, 60, 70, 80, 90 }; 

     int low, high, user_input, mid; 

     private void textBox1_TextChanged(object sender, EventArgs e) 
     { 

      user_input = Convert.ToInt32(textBox1.Text); 

      while (low <= high) 
      { 
       mid = (low + high)/2; 


       if (arr[mid] < user_input) 
       { 
        low = mid + 1; 
        continue; 
       } 
       else if (arr[mid] > user_input) 
       { 
        high = mid - 1; 
        continue; 
       } 

       else 
       { 
        MessageBox.Show(mid.ToString()); 
       } 
      } 
      MessageBox.Show("-1".ToString()); 

     } 
    } 
} 

但我不斷收到或者-1作爲輸出，或者如果我進入一個零的0無限循環進入。

請幫忙嗎？

Answer 1

我已初始化low和high變量，並在找到匹配項後添加return聲明。 這裏是更正後的代碼（注意評論）：

using System; 
using System.Collections.Generic; 
using System.ComponentModel; 
using System.Data; 
using System.Drawing; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 
using System.Windows.Forms; 

namespace arra3 { 
    public partial class Form1 : Form 
    { 
     public Form1() 
     { 
      InitializeComponent(); 
     } 

     int[] arr = { 0, 10, 20, 30, 40, 50, 60, 70, 80, 90 }; 

     int low, high, user_input, mid; 

     private void textBox1_TextChanged(object sender, EventArgs e) 
     { 

      user_input = Convert.ToInt32(textBox1.Text); 
      low = 0; // <- HERE 
      high = arr.Length; // <- HERE 

      while (low <= high) 
      { 
       mid = (low + high)/2; 


       if (arr[mid] < user_input) 
       { 
        low = mid + 1; 
        continue; 
       } 
       else if (arr[mid] > user_input) 
       { 
        high = mid - 1; 
        continue; 
       } 

       else 
       { 
        MessageBox.Show(mid.ToString()); 
        return; // <- HERE 
       } 
      } 
      MessageBox.Show("-1".ToString()); 

     } 
    } 
}