二分法查找某值的索引 c算法

[c]代码库

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define MAX 10
#define SWAP(x,y) {int t; t = x; x = y; y = t;}

void quicksort ( int[], int, int );
int bisearch ( int[], int );

int main ( void )
{
	int number[MAX] = {0};
	int i, find;
	srand ( time ( NULL ) );

	for ( i = 0; i < MAX; i++ )
	{
		number[i] = rand() % 100;
	}

	quicksort ( number, 0, MAX-1 );

	printf ( "数列：" );
	for ( i = 0; i < MAX; i++ )
		printf ( "%d ", number[i] );

	printf ( "\n输入寻找对象：" );
	scanf ( "%d", &find );

	if ( ( i = bisearch ( number, find ) ) >= 0 )
		printf ( "找到数字于索引 %d ", i );
	else
		printf ( "\n找不到指定数" );

	printf ( "\n" );

	return 0;
}

int bisearch ( int number[], int find )
{
	int low, mid, upper;

	low = 0;
	upper = MAX - 1;

	while ( low <= upper )
	{
		mid = ( low+upper ) / 2;
		if ( number[mid] < find )
			low = mid+1;
		else if ( number[mid] > find )
			upper = mid - 1;
		else
			return mid;
	}

	return -1;
}

void quicksort ( int number[], int left, int right )
{
	int i, j, k, s;

	if ( left < right )
	{
		s = number[ ( left+right ) /2];
		i = left - 1;
		j = right + 1;

		while ( 1 )
		{
			while ( number[++i] < s ) ;  // 向右找
			while ( number[--j] > s ) ;  // 向左找
			if ( i >= j )
				break;
			SWAP ( number[i], number[j] );
		}

		quicksort ( number, left, i-1 );   // 对左边进行递回
		quicksort ( number, j+1, right );  // 对右边进行递回
	}
}