Constructors

A constructor initializes a new object when it is created.
constructor A constructor has the same name as the class and runs automatically for each new object.
                            example
                            name = "Ada", startingScore = 10 (default)name = "Bjarne"name = "Grace"startingScore = 0startingScore = 25
                        

                            constructors.cpp
                        
Replay: real traced execution (multi-file project)

                            #include <iostream>
#include <string>

class Player {
public:
    std::string name;
    int score;

    Player(std::string playerName, int startingScore) {
        name = playerName;
        score = startingScore;
    }
};

int main() {
    std::string name = "Ada";
    int startingScore = 10;

    Player player(name, startingScore);

    std::cout << "player=" << player.name << std::endl;
    std::cout << "score=" << player.score << std::endl;
    return 0;
}
#include <iostream>
#include <string>

class Player {
public:
    std::string name;
    int score;

    Player(std::string playerName, int startingScore) {
        name = playerName;
        score = startingScore;
    }
};

int main() {
    std::string name = "Bjarne";
    int startingScore = 10;

    Player player(name, startingScore);

    std::cout << "player=" << player.name << std::endl;
    std::cout << "score=" << player.score << std::endl;
    return 0;
}
#include <iostream>
#include <string>

class Player {
public:
    std::string name;
    int score;

    Player(std::string playerName, int startingScore) {
        name = playerName;
        score = startingScore;
    }
};

int main() {
    std::string name = "Grace";
    int startingScore = 10;

    Player player(name, startingScore);

    std::cout << "player=" << player.name << std::endl;
    std::cout << "score=" << player.score << std::endl;
    return 0;
}
#include <iostream>
#include <string>

class Player {
public:
    std::string name;
    int score;

    Player(std::string playerName, int startingScore) {
        name = playerName;
        score = startingScore;
    }
};

int main() {
    std::string name = "Ada";
    int startingScore = 0;

    Player player(name, startingScore);

    std::cout << "player=" << player.name << std::endl;
    std::cout << "score=" << player.score << std::endl;
    return 0;
}
#include <iostream>
#include <string>

class Player {
public:
    std::string name;
    int score;

    Player(std::string playerName, int startingScore) {
        name = playerName;
        score = startingScore;
    }
};

int main() {
    std::string name = "Ada";
    int startingScore = 25;

    Player player(name, startingScore);

    std::cout << "player=" << player.name << std::endl;
    std::cout << "score=" << player.score << std::endl;
    return 0;
}

                        
1name ← Ada, startingScore ← 10⋯15int main() {16    std::string name→ Ada = "Ada"; //@name="Bjarne", "Grace"17    int startingScore→ 10 = 10; //@startingScore=0, 251819    Player player(nameAda, startingScore);⋯
2score ← 10⋯9Player(std::string playerNameAda, int startingScore10) {10    name = playerNameAda;11    score→ 10 = startingScore10;12}⋯
3player ← (empty)⋯19    Player player→ (empty)(nameAda, startingScore);2021    std::cout << "player=" << player(empty).name << std::endl;22    std::cout << "score=" << player(empty).score << std::endl;23    return 0;24}⋯outputplayer=Ada
score=10
1name ← Bjarne, startingScore ← 10⋯15int main() {16    std::string name→ Bjarne = "Bjarne";17    int startingScore→ 10 = 10;1819    Player player(nameBjarne, startingScore);⋯
2score ← 10⋯9Player(std::string playerNameBjarne, int startingScore10) {10    name = playerNameBjarne;11    score→ 10 = startingScore10;12}⋯
3player ← (empty)⋯19    Player player→ (empty)(nameBjarne, startingScore);2021    std::cout << "player=" << player(empty).name << std::endl;22    std::cout << "score=" << player(empty).score << std::endl;23    return 0;24}⋯outputplayer=Bjarne
score=10
1name ← Grace, startingScore ← 10⋯15int main() {16    std::string name→ Grace = "Grace";17    int startingScore→ 10 = 10;1819    Player player(nameGrace, startingScore);⋯
2score ← 10⋯9Player(std::string playerNameGrace, int startingScore10) {10    name = playerNameGrace;11    score→ 10 = startingScore10;12}⋯
3player ← (empty)⋯19    Player player→ (empty)(nameGrace, startingScore);2021    std::cout << "player=" << player(empty).name << std::endl;22    std::cout << "score=" << player(empty).score << std::endl;23    return 0;24}⋯outputplayer=Grace
score=10
1name ← Ada, startingScore ← 0⋯15int main() {16    std::string name→ Ada = "Ada";17    int startingScore→ 0 = 0;1819    Player player(nameAda, startingScore);⋯
2Player(std::string playerName, int startingScore)⋯9Player(std::string playerNameAda, int startingScore0) {10    name = playerNameAda;11    score0 = startingScore0;12}⋯
3player ← (empty)⋯19    Player player→ (empty)(nameAda, startingScore);2021    std::cout << "player=" << player(empty).name << std::endl;22    std::cout << "score=" << player(empty).score << std::endl;23    return 0;24}⋯outputplayer=Ada
score=0
1name ← Ada, startingScore ← 25⋯15int main() {16    std::string name→ Ada = "Ada";17    int startingScore→ 25 = 25;1819    Player player(nameAda, startingScore);⋯
2score ← 25⋯9Player(std::string playerNameAda, int startingScore25) {10    name = playerNameAda;11    score→ 25 = startingScore25;12}⋯
3player ← (empty)⋯19    Player player→ (empty)(nameAda, startingScore);2021    std::cout << "player=" << player(empty).name << std::endl;22    std::cout << "score=" << player(empty).score << std::endl;23    return 0;24}⋯outputplayer=Ada
score=25