二分查找-------一般查找

二分查找-------一般查找

二分查找
 
 
#include <stdio.h>
#define N 10
int f(int a[],int low,int high,int x)
{
    int mid  ;
    while(low<=high) 
      
    { 
    mid=(low+high)/2 ;
    if(a[mid]==x)  return mid ;
    else    if(a[mid]<x)  return f(a,mid+1,high,x) ;
      else   f(a,low,mid-1,x);
     }
     return -1 ;
}
int main ( )
{
      
     int x, a[N]={ -1,12,23,42,56,65,81,92,100,109} ;
     scanf("%d",&x);
      
    printf("%d
",f(a,0,N-1,x));
 
}
 
 
 
 
 
一般查找
 
 
#include <stdio.h>
int main (  )
{
int i,x, a[10]={ -1,12,23,42,56,65,81,92,100,109} ;
     scanf("%d",&x);
     for(i=0;i<10;i++) 
     if (a[i]>x)   printf("%d",i-1);
     
    return 0;
}
　　

 

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