题目链接:http://poj.org/problem?id=2105
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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
题意:非常easy, 就是每一个案例给出一个32位的2进制数字串。 要求依照每8位转换为8进制输出(中间有‘.’)就可以!
代码例如以下:
#include <iostream> #include <cmath> using namespace std; int main() { int N; int i, j; char s[117]; while(cin >> N) { while(N--) { cin>>s; int ans[4], k = 7, l = 0; int sum = 0; for(i = 0; i < 32; i++) { sum +=(s[i]-'0')*pow(2.0,k); k--; if(i%8==7) { ans[l++] = sum; sum = 0; k = 7; } } cout<<ans[0]<<'.'<<ans[1]<<'.'<<ans[2]<<'.'<<ans[3]<<endl; } } return 0; }