Строковые переменные (символьные массивы)

#include <iostream>
#include <string>
 
using namespace std;
 
int _tmain(int argc, _TCHAR* argv[])
{
    string firstname, lastname, fname;
 
    getline(cin, firstname);
    getline(cin, lastname);
    
    int l1 = firstname.length();
    cout<<"length of the line \"firstname\" = "<<l1<<endl;
    int l2 = lastname.length();
    cout<<"length of the line \"lastname\" = "<<l2<<endl;
    cout<<"lexis = "<<l1-l2<<endl;
    fname=firstname+lastname;
    cout<<"Concat"<<fname<<endl;
    system("pause");
    return 0;
}

#include <iostream>
#include <cstring>
 
int main()
{
    char name[20];
    std::cout << "name: ";
    if(!std::cin.getline(name, sizeof(name))) return 1;
 
    char surname[20];
    std::cout << "surname: ";
    if(!std::cin.getline(surname, sizeof(surname))) return 1;
 
    std::cout << "the length of 'name': " << std::strlen(name) << '\n';
    std::cout << "the length of 'surname': " << std::strlen(surname) << '\n';
 
    int lexical_relationship = std::strcmp(name, surname);
    std::cout << "lexical relationship: ";
 
    if(lexical_relationship < 0)
        std::cout << "'name' < 'surname'\n";
    else if(lexical_relationship > 0)
        std::cout << "'name' > 'surname'\n";
    else
        std::cout << "'name' = 'surname'\n";
 
    char buf[40] = "";
    std::strcat(buf, name);
    std::strcat(buf, surname);
    std::cout << "concatenation: " << buf << '\n';
}