建民打卡日记4.22

一、问题描述

输入N个数组成的有序数列，在数组中查找某个数的位置，若找到，输出下标，否则输出not found

二、流程设计

1.取数组最大值最小值下标high和low

2.将待查找数与中值比较，若小于中值则查找前半段，否则查找后半段

3.输出结果

三、流程图设计

四、代码实现

#include <iostream>
using namespace std;
#define N 10

int main() {
	int i, a[N] = {-3, 4, 7, 9, 13, 45, 67, 89, 100, 180}, low = 0, high = N - 1, mid, k = -1, m;
	for (i = 0; i < N; i++) {
		printf("%d", a[i]);
	}
	cin >> m;
	while (low <= high) {
		mid = (low + high) / 2;
		if (m < a[mid])
			high = mid - 1;
		else if (m > a[mid])
			low = mid + 1;
		else {
			k = mid;
			break;
		}
	}
	if (k >= 0)
		printf("m=%d,index=%d\n", m, k);
	else
		printf("Not be found!\n");
}