OpenJudge/Poj 2105 IP Address

1.链接地址：

http://poj.org/problem?id=2105

http://bailian.openjudge.cn/practice/2105

2.题目：

IP Address

Time Limit: 1000MS		Memory Limit: 30000K
Total Submissions: 18146		Accepted: 10456

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

3.思路：

4.代码：

#include "stdio.h"
#include "stdlib.h"

int f(char input[],int start)
{
    int ans=0;
    int i;
    for(i=0;i<8;i++)
    {
       ans=ans*2+(input[i+start]-'0');
    }
    return ans;
}
int main()
{
    int a,b,c,d;
    int n;
    int i;
    char input[34];
    scanf("%d
",&n);
    for(i=0;i<n;i++)
    {
        gets(input);
        a=f(input,0);
        b=f(input,8);
        c=f(input,16);
        d=f(input,24);
        printf("%d.%d.%d.%d
",a,b,c,d);
    }
    //system("pause");
    return 0;
}