对分查找

对于一个排好序的数组，可以使用对分查找算法来查找元素。

#include <stdio.h>int binarySearch(int a[],int low,int high,int key){    /*a-->待查找数组,      low-->下边界,      high-->上边界,      key-->待查找元素*/    if(low > high){        return -1;    }    int mid = (low + high)/2;    if(key == a[mid]){        return mid;    }    if(key < a[mid]){        return binarySearch(a,low,mid-1,key);    }    else{        return binarySearch(a,mid+1,high,key);    }}int main(void){    int a[] = {4,1,7,5,2,8,6,9};    int index = binarySearch(a,0,7,8);    printf("Index:%d ===> Value:%d",index,a[index]);    getchar();}

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