#include <iostream>

using namespace std;

int main() {

    string greeting = "Hello"; 
    cout << greeting << endl;

    string firstName = "John";
    string lastName = "Doe";
    string fullName = firstName + " " + lastName;
    cout << fullName << endl; 

    fullName = firstName.append(" ").append(lastName);
    cout << fullName << endl; 

    cout << "The length of the txt string is: " << fullName.length() << endl;

    // 竖着打印
    for (int i = 0; i < fullName.length(); i++) {
        cout << fullName[i] << endl;
    }

    // 转义字符
    cout << "We are the so-called \"Vikings\" from the north." << endl;
}