折半查找算法

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/*
find方法利用折半查找算法查找整数m在数组中的位置。若找到返回其下标值，反之返回-1
*/
#include <stdio.h>
#define M 5
int main() {
	int find(int data[], int num);// 函数声明
	int data[5] = {23, 45, 123, 222, 254};
	int i = 0, result = 0;
	int num = 0;
	printf("The datas of data[5] are：\n");
	for(i = 0; i < M; i++) {
		printf("%d\t", data[i]);
	}

	printf("\nPlease input the num you want to find:\n");
	scanf("%d", &num);
	result = find(data, num);
	if(result >= 0) {
		printf("The index is %d\n", result);
	} else {
		printf("Not be find!!\n");
	}
	return 0;
}

// 折半查找算法
int find(int data[], int num) {
	int low = 0, high = M-1, mid = 0;
	while(low <= high) {
		mid = (low + high) / 2;
		if(num < data[mid]) {
			high = mid - 1;
		} else if(num > data[mid]) {
			low =  mid + 1;
		} else {
			return mid;
		}
	}
	return -1;
}