Person Invariants

Define a Person class with private member variables name, age, and h2eight. Add a public constructor to initialize these variables and public methods to get and set their values. Ensure age and height are positive. Create instances of Person and demonstrate the use of its methods.

Answer

#include <iostream>
#include <string>

class Person {
private:
    std::string name;
    int age;
    float height;

public:
    // Constructor to initialize member variables
    Person(const std::string& person_name, int person_age, float person_height) 
        : name(person_name), age(person_age), height(person_height) {
        if (age < 0) age = 0; // Ensure age is positive
        if (height < 0) height = 0; // Ensure height is positive
    }

    // Getter for name
    std::string get_name() const {
        return name;
    }

    // Setter for name
    void set_name(const std::string& person_name) {
        name = person_name;
    }

    // Getter for age
    int get_age() const {
        return age;
    }

    // Setter for age with validation
    void set_age(int person_age) {
        if (person_age >= 0) {
            age = person_age;
        } else {
            std::cout << "Age must be positive." << std::endl;
        }
    }

    // Getter for height
    float get_height() const {
        return height;
    }

    // Setter for height with validation
    void set_height(float person_height) {
        if (person_height >= 0) {
            height = person_height;
        } else {
            std::cout << "Height must be positive." << std::endl;
        }
    }

    // Print person details
    void print_details() const {
        std::cout << "Name: " << name << std::endl;
        std::cout << "Age: " << age << std::endl;
        std::cout << "Height: " << height << " cm" << std::endl;
    }
};

// `main` is here for demonstration purposes only
int main() {
    // Create instances of Person
    Person person1("Alice", 30, 165.5);
    Person person2("Bob", -5, 180.0); // Invalid age
    Person person3("Charlie", 25, -170.0); // Invalid height

    // Print initial details
    std::cout << "Person 1 details:" << std::endl;
    person1.print_details();
    std::cout << std::endl;

    std::cout << "Person 2 details:" << std::endl;
    person2.print_details();
    std::cout << std::endl;

    std::cout << "Person 3 details:" << std::endl;
    person3.print_details();
    std::cout << std::endl;

    // Set new values
    person1.set_name("Alicia");
    person1.set_age(35);
    person1.set_height(167.0);

    // Attempt to set invalid values
    person2.set_age(-10);
    person3.set_height(-175.0);

    // Print updated details
    std::cout << "Updated Person 1 details:" << std::endl;
    person1.print_details();
    std::cout << std::endl;

    std::cout << "Updated Person 2 details (after attempting to set invalid age):" << std::endl;
    person2.print_details();
    std::cout << std::endl;

    std::cout << "Updated Person 3 details (after attempting to set invalid height):" << std::endl;
    person3.print_details();

    return 0;
}