email address validator

email_val.cpp

#include <string>
#include <iostream>

using namespace std;

bool chck_email(string);

int main()
{
    string str;
    cout << "enter an email address: ";
    getline(cin, str);
    if(chck_email(str))
    cout << "this is an email address" << endl;
    else
    cout << "this is not an email address" << endl;
    
    return 0;
}

bool chck_email(string chck)
{
    string getdomain;
    int countstring1 = 0, countstring2 = 0, countstring3 = 0;
    for(int c = 0; c < chck.length(); c++)
    {
        if(chck.at(c) == '@'){
            countstring1++;
            countstring3++;
        for(; countstring1 < chck.length(); countstring1++){
            if(chck.at(countstring1) == '.'){
                    countstring2++;
                    countstring2 = countstring2 + countstring3;
                    getdomain = chck.substr(countstring2, int(chck.length()));
                    if(getdomain == "com" || getdomain == "org" || getdomain == "net" || getdomain == "int" || getdomain == "edu" || getdomain == "gov" || getdomain == "mil"){
                        return true;
                    }
                    else{
                        return false;
                    }
            }
            else{
                countstring2++;
                continue;
            }

        }
        }
        else{
            countstring1++;
            countstring3++;
            continue;
        }
    }
    return false;
    
}