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\n",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;
}