Discussion on: Daily Challenge #89 - Extract domain name from URL

[Harsh Saglani]

O(N) approach:

#include<iostream>
#include <string>
using namespace std;
string domainName(string url)
{
    string domain = "";
    bool flag = true;
    for(int i = 0; i < url.size(); i++)
    {
        if(flag)
        {
            if(url[i] == '/')
            {
                flag = false;
                i+=2;
                if(url[i] == 'w')
                    i = i+3;
                else
                    i--;
            }
            continue;
        }
        else if(url[i] == '.')
            return domain;
        domain += url[i];
    }
    return domain;
}
int main()
{
    string url;
    cin >> url;
    cout << domainName(url) << endl;
    return 0;
}

Naive approach:

#include<iostream>
#include <string>
using namespace std;
string domainName(string url)
{
    int x = url.find("www");
    if(x==string::npos)
    {
        x = url.find("//");
        x+=2;
    }
    else
        x+=4;
    return url.substr(x,url.find(".com")-x);
}
int main()
{
    string url;
    cin >> url;
    cout << domainName(url) << endl;
    return 0;
}