poj 2105 IP Address

IP Address

Time Limit: 1000MS		Memory Limit: 30000K
Total Submissions: 18951		Accepted: 10939

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: 

2

⁷

   2

⁶

  2

⁵

  2

⁴

  2

³

   2

²

  2

¹

  2

⁰

 

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

 

分析：

进制转换

#include <cstdio>
#include<algorithm>
#include<iostream>
#include<string>
#include<cstring>
#include<vector>
using namespace std;
int b[8]={128,64,32,16,8,4,2,1};
int main(){
    int n;
    string s;
    while(cin>>n){
        while(n--){
            cin>>s;
            int i,j,k=0;
            for(i=0;i<=31;){
                int sum=0;
                j=0;
                while(j<8){
                    if(s[i]=='1')
                    sum+=b[i%8];
                    i++;
                    j++;
                }
                cout<<sum;
                if(k<3){
                    cout<<'.';
                }
                else{
                    cout<<endl;
                }
                k++;
            }
        }
    }
    return 0;
}