Binary Find/binary find

Two-point lookup is also called binary lookup.

The premise: the array is ordered.

Thought: 1, each time take the middle number of key to compare, if equal, find;

2, if key > middle number, indicating that key is on the right side of the middle number, then the right side of the middle number and key comparison;

3, if key < Middle number, indicating that key is on the left side of the middle number, and then take the left of the middle number and key comparison;

4, cycle the above process;

Don't say anything, on the code:

1#include <stdio.h>2 3 intMainintargcConst Char*argv[]) {4     5     //Defining Arrays6     intArr[] = {Ten, $, the, the, -,122,456,789,999};7     8     //Find 789 subscript in this array9     intKey =789;Ten      One     intLen =sizeof(arr)/sizeof(arr[0]); A      -     intMinindex =0; -     intMaxindex = Len-1; the     intMiddleindex = len/2;//Subscript of the middle number -      -     //determine if the middle number equals key -     if(Key = =Arr[middleindex]) { +printf"The key ' s index is%d", Middleindex); -         return 0; +     } A      at     //if not equal, size is judged -      while(Key! =Arr[middleindex]) { -         if(Key < Arr[middleindex]) {//Note Key is on the left of the middle number -Maxindex = Middleindex-1;//maximum subscript to the subscript of the previous element of the intermediate number subscript -         } -         Else if(Arr[middleindex < key]) {//Note Key is on the right of the middle number inMinindex = Middleindex +1;//The minimum subscript changes to the subscript of an element after the middle number of the underlying -         } to         Else{//Description key = Arr[middleindex] +printf"The key ' s index is%d", Middleindex); -             return 0; the         } *Middleindex = (Minindex + maxindex)/2; $     }Panax Notoginseng      -printf"the number to find is not found"); the      +     return 0; A}

Binary Find/binary find