ipAddress.cpp

#include<bits/stdc++.h>
using namespace std;

bool valid_subpart(string s, int i, int j){

    int len = j-i+1;

    if(len >3)
        return false;

    if(s[i] == '0')
    {
        if(len == 1) return true;
        return false;
    }

    int num = stoi(s.substr(i,j-i+1));

    if(num>=0 && num<=255)
        return true;

    return false;
}

bool valid_ip(string s, int len, int i, int j, int k)
{

    if( valid_subpart(s,0,i) &&
        valid_subpart(s,i+1,j) &&
        valid_subpart(s,j+1,k) &&
        valid_subpart(s,k+1,len-1 ) )
        return true;

    return false;
}

void add_string(string s, int n, int i, int j, int k,vector<string> &res){
    string temp;

    temp.append(s.substr(0,i+1));

    temp.push_back('.');
    temp.append(s.substr(i+1,j-i));

    temp.push_back('.');
    temp.append(s.substr(j+1,k-j));

    temp.push_back('.');
    temp.append(s.substr(k+1,n-k-1));

    res.push_back(temp);
}

vector<string> genIp(string &s) {

    int i,j,k,n;
    vector<string> res;
    n = s.length();

    for(i=0;i<n-3;i++){

        for(j=i+1;j<n-2;j++){

            for(k=j+1;k<n-1;k++){

                if(valid_ip(s,n,i,j,k)){

                    add_string(s,n,i,j,k,res);
                }
            }
        }
    }
    return res;
}
int main()
{
    cout<<endl<<"==== IP ADDRESS GENERATOR ===="<<endl;

    string ipString;
    cout<<endl<<"Inputs Section : ";

    cout<<endl<<"Enter the numbers with which you wanna generate IP Address : ";
    cin>>ipString;


    vector<string> ans = genIp(ipString);

    if (ans.size() == 0){
        cout<<endl<<"Error : IP Address with the numbers given "<<ipString<<" not Possible -_-"<<endl;
    }

    else{
        cout<<"Your Problem solved..........."<<endl;
        cout<<"The IP address found are : "<<endl<<endl;
        cout<<endl<<"==========================================="<<endl<<endl<<endl;
        for (int i = 0;i<ans.size();i++){
            cout<<" | "<<"IP ADDDRESS "<<i+1<<" : "<<ans[i]<<" | "<<endl<<endl;
        }
        cout<<endl<<"==========================================="<<endl;
    }
}