تحديات برمجيةالتحدي الثاني - حل التمرين الرابع بلغة C++

#include <iostream>
#include <string>

int main() {

    std::string S1, S2, S3, S4="";

    std::cout << "Enter S1: ";
    getline(std::cin, S1);

    std::cout << "Enter S2: ";
    getline(std::cin, S2);

    std::cout << "Enter S3: ";
    getline(std::cin, S3);

    std::cout << "---------------------------------------\n";

    // Part 1
    std::cout << "The concatenation of S1 and S2 is equal S3? "
        << ((S3 == (S1 + S2)) ? "True" : "False")
        << "\n";
    
    // Part 2
    std::cout << "S1 is part of S2 or S1=S2? "
        << ((S2.find(S1, 0) != std::string::npos) ? "True" : "False")
        << "\n";
    
    // Part 3
    if (S1.length() > S2.length()) {
        S4 = S2 + S1;
    }
    
    // Part 4
    if (S2.length() > S1.length()) {
        S4 = S1 + S2;
    }
    
    // Part 5
    std::cout << "S2 is part of the second half of S1? " 
        << ((S1.find(S2, S1.length() / 2) != std::string::npos) ? "True" : "False")
        << "\n";
    
    // Part 6
    std::cout << "The first half characters of S1 are: ";
    for (int i = 0; i < S1.length() / 2; i++) {
        std::cout << S1[i];
    }

    char end; std::cin >> end;
    return 0;

}