华东师大OJ：IP Address【IP地址转换】

/*=====================================
 IP Address
Time Limit:1000MS Memory Limit:30000KB
Total Submit:3394 Accepted:1530 Special Judge
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
Mexico and Central America Region 2004 
======================================*/

 1 #include<stdio.h>
 2 int main()
 3 {
 4     int a[4]={0},i,j,k;
 5     char ch;
 6     int N;
 7     freopen("ip.in","r",stdin);
 8     scanf("%d",&N);
 9     getchar();//接收回车符 
10     for(k=0;k<N;k++)
11     {
12         for(i=0;i<4;i++)
13         {
14             a[i]=0;
15             for(j=0;j<8;j++)
16             {
17                 ch=getchar();
18                 a[i]=a[i]*2+(ch-'0');
19             }
20         }
21         getchar();//接收回车符 
22         printf("%d.%d.%d.%d\n",a[0],a[1],a[2],a[3]);
23     }
24     return 0;
25 }