poj 2105 IP Adress

/*

 * http://sosal.tistory.com/
 * made by so_Sal
 */

IP Address

Time Limit: 1000MS		Memory Limit: 30000K
Total Submissions: 18283		Accepted: 10535

Description

Suppose you are reading byte streams from any device, representing IP addresses. Your task is to convert a 32 characters long sequence of '1s' and '0s' (bits) to a dotted decimal format. A dotted decimal format for an IP address is form by grouping 8 bits at a time and converting the binary representation to decimal representation. Any 8 bits is a valid part of an IP address. To convert binary numbers to decimal numbers remember that both are positional numerical systems, where the first 8 positions of the binary systems are: 

27   26  25  24  23   22  21  20 

128 64  32  16  8   4   2   1 

Input

The input will have a number N (1<=N<=9) in its first line representing the number of streams to convert. N lines will follow.

Output

The output must have N lines with a doted decimal IP address. A dotted decimal IP address is formed by grouping 8 bit at the time and converting the binary representation to decimal representation.

Sample Input

4
00000000000000000000000000000000 
00000011100000001111111111111111 
11001011100001001110010110000000 
01010000000100000000000000000001 

Sample Output

0.0.0.0
3.128.255.255
203.132.229.128
80.16.0.1

Source

México and Central America 2004

8자리 문자열을 통해 이진수를 받아서 10진수로 바꿔주는 함수만 만들면

매우 쉽게 해결할 수 있습니다.

#include<iostream>
#include<vector>
#include<algorithm>
#include<iomanip>
#include<string>
#include<cmath>

using namespace std;

int convert(string input){
	int result = 0;

	for(int i=0;i<input.size();i++){
		if(input[i] == '1'){
			result+= pow((double)2,7-i);
		}
	}
	return result;
}

int main(void){


	int n;
	cin>>n;
	string input;
	for(int i=0;i<n;i++){
		input.clear();
		cin>>input;
		string a = input.substr(0,8);
		string b = input.substr(8,8);
		string c = input.substr(16,8);
		string d = input.substr(24,8);

		cout<<convert(a)<<"."<<convert(b)<<"."<<convert(c)<<"."<<convert(d)<<endl;
	}
}