C/C++ 整数二分以及浮点数二分

本文介绍: /k为查找的数while (i+1!return i;re turn 0;//k为查找的数while (i+1!return i;r eturn 0;

#include<stdio.h&gt;
int q[] = { 1,2,3,3,7,7,7,8,9 }, k = 3;//k为查找的数
int Binary_search(int q[], int l, int r) {
	int i = l - 1, j = r + 1, mid;
	while (i+1 != j) 
	{
		mid = (i + j) &gt;&gt; 1;
		//分界点是小于等于k的在左边，大于k的在右边，所以直接返回 j 就是答案
		if (q[mid] <= k)
		{
			i = mid;
		}
		else
		{
			j = mid;
		}
	}
	return j;
}
int main() {
	
	int len = sizeof(q) / sizeof(q[0]);
	int res = Binary_search(q, 0, len - 1);

	printf("%d", res);
	return 0;
}

#include<stdio.h&gt;
int q[] = { 1,2,3,3,7,7,7,8,9 }, k = 3;//k为查找的数
int Binary_search(int q[], int l, int r) {
	int i = l - 1, j = r + 1, mid;
	while (i+1 != j) 
	{
		mid = (i + j) &gt;&gt; 1;
		
		if (q[mid] < k)
		{
			i = mid;
		}
		else
		{
			j = mid;
		}
	}
	return j;
}
int main() {
	
	int len = sizeof(q) / sizeof(q[0]);
	int res = Binary_search(q, 0, len - 1);

	printf("%d", res);
	return 0;
}

#include<stdio.h&gt;
int q[] = { 1,2,3,3,7,7,7,8,9 }, k = 3;//k为查找的数
int Binary_search(int q[], int l, int r) {
	int i = l - 1, j = r + 1, mid;
	while (i+1 != j) 
	{
		mid = (i + j) >> 1;
		
		if (q[mid] <= k)
		{
			i = mid;
		}
		else
		{
			j = mid;
		}
	}
	return i;
}
int main() {
	
	int len = sizeof(q) / sizeof(q[0]);
	int res = Binary_search(q, 0, len - 1);

	printf("%d", res);
	return 0;
}

#include<stdio.h>
int q[] = { 1,2,3,3,7,7,7,8,9 }, k = 3;//k为查找的数
int Binary_search(int q[], int l, int r) {
	int i = l - 1, j = r + 1, mid;
	while (i+1 != j) 
	{
		mid = (i + j) >> 1;
		
		if (q[mid] < k)
		{
			i = mid;
		}
		else
		{
			j = mid;
		}
	}
	return i;
}
int main() {
	
	int len = sizeof(q) / sizeof(q[0]);
	int res = Binary_search(q, 0, len - 1);

	printf("%d", res);
	return 0;
}

#include<iostream>
using namespace std;
#include<cstdio>
#include<algorithm>
double x;

double max(double x, double y)
{
	return x > y ? x : y;
}

double fBi_search(double l, double r) 
{
	double mid;
	while (r - l > 1e-8) 
	{
		mid = (l + r) / 2;
		if (mid * mid <= x)
		{
			l = mid;
		}
		else
		{
			r = mid;
		}
	}
	return l;
}
int main() 
{
	//求根号x
	cin >> x;
	cout<<fBi_search(0, max(1, x));
	return 0;
}