习题4-5 IP网络 UVa 1590

#include <iostream> #include <string> #include <vector> #include <sstream> #include <fstream> using namespace std; string binary(const unsigned int val,string s) { for(int i = 7; i >= 0; i--) { if(val & (1 << i)) s.push_back('1'); else s.push_back('0'); } return s; } //二进制IP转换成十进制IP string Todec(string binaryIP) { stringstream s; string temp; string dec; for(int i=0;i<4;i++)//4组8位二进制码 { for(int j=9*i;j<(9*i+8);j++) { s<<binaryIP[j]; } s>>temp; int number=stoi(temp,nullptr,2); s.clear(); s.str(""); s<<number; string tempdec; s>>tempdec; dec+=tempdec+"."; s.clear(); s.str(""); } dec.pop_back(); return dec; } string ToBinary(string ip)//生成二进制的IP码 { stringstream s; string binaryIP; for(int i=0;i<ip.length();i++) { if(ip[i]!='.') s<<ip[i]; if(ip[i]=='.'||(i==ip.length()-1)) { int a=0; s>>a; string binary8; binary8=binary(a,binary8); //两个函数都是必要的，一个是清空s中的内容，一个是重置s的状态标志位 s.str(""); s.clear(); if(binaryIP.size()==0) binaryIP+=binary8; else binaryIP+="|"+binary8; } } return binaryIP; } //返回比较后的二进制码并且传引用返回不相同位数 string compare(string binary1,string binary2,int &n)//1为当前最小串，2为新的值 { int countpoint=0; for(int i=0;i<binary1.size();i++) { if(binary1[i]!=binary2[i]) { for(int j=i;j<binary1.size();j++) { if(binary1[j]!='|') binary1[j]='0'; else countpoint++; } if((binary1.length()-i)>n) n=binary1.length()-i-countpoint; break; } } return binary1; } int main() { int n; while(cin>>n) { string temp;//保存目前的最小ip bool first=1; int notSame=0;//不相同的位数 while(n--) { string ip; cin>>ip; string binaryIP; binaryIP=ToBinary(ip); if(first==1) { temp=binaryIP; first=0; } else if(first==0) { int ¬SameCopy=notSame; temp=compare(temp,binaryIP,notSameCopy); } } string answer; answer=Todec(temp); cout<<answer<<endl; string answer2; for(int i=0;i<4;i++) { for(int j=8*i;j<(8*i+8);j++) { if(j>=(32-notSame)) answer2.push_back('0'); else answer2.push_back('1'); } if(i!=3) answer2.push_back('|'); } cout<<Todec(answer2)<<endl; } }