[UVA](11461)Square Numbers ---完全平方数

A square number is an integer number whose square root is also an integer. For example 1, 4, 81 are some square numbers. Given two numbers a and b you will have to find out how many square numbers are there between a and b (inclusive).

 

Input

The input file contains at most 201 lines of inputs. Each line contains two integers a and b (0<a≤b≤100000). Input is terminated by a line containing two zeroes. This line should not be processed.

 

Output

For each line of input produce one line of output. This line contains an integer which denotes how many square numbers are there between a and b (inclusive).

Sample Input

1 4

1 10

0 0

Sample Output

2

3

#include<iostream>
#include<cmath>
#include<cstdio>
using namespace std;
int main()
{
    int a;
    int b;
    while(scanf("%d %d",&a,&b)&& a && b)
    {
        cout<<int(sqrt(b))-int(ceil(sqrt(a)))+1<<endl;
    }
    return 0;
}

题意：给你一个区间[a,b]让你求这个区间内有多少个完全平方数

解法：观察连续平方数如：1,4,9,16,25,36,49……将他们开方后1,2,3,4,5……就会发现规律了。

注意：左端点开方后得到的小数，在保留成整数的时候，要四舍五入。例如[7,64]  sqrt(7)=2,   sqrt(64)=8  8-2+1=7 然而[7,64]之间的完全平方数有

9,16,25,36,49,64这6个 ，显然不对,所以要用到celi这个函数。

函数名： ceil

用 法： double ceil(double x);

功 能： 返回大于或者等于指定表达式的最小整数

头文件：math.h

返回数据类型：double

可以记住这个，一个小小的数论。