Exercises 1.15 Coding Practice

1.

Write the Cake structure, which has instance variables name, weight and member function has_icing function that returns a bool. Use the Cake object initialised below to invoke the has_icing function.

#include <iostream>
using namespace std;

// Write your code for the struct Cake here.

int main() {
    Cake c = { "Choco lava", 3.5};
    // Write your code to invoke the has_icing function here
}

Solution.

Below is one way to implement the program. We declare the Cake struct and list the instance variables in order.

#include <iostream>
using namespace std;

struct Cake {
    string name;
    double weight;
    bool has_icing;
};

int main() {
     Cake c = { "Choco lava", 3.5};
     cout << c.has_icing() << endl;
}

2.

The Cake structure has instance variables name, weight and member function has_icing. Write the has_icing function which returns true when the weight is greater than 10.

#include <iostream>
using namespace std;

struct Cake {
    string name;
    double weight;
    bool has_icing();
};

// Write your code for the has_icing function

int main() {
     Cake c = {"Choco lava", 3.5};
}

Solution.

Below is one way to implement the program.

#include <iostream>
using namespace std;

struct Cake {
    string name;
    double weight;
    bool has_icing();
};

bool Cake::has_icing() {
     if (weight > 10) {
       return true;
     }
     else {
       return false;
     }
}

int main() {
     Cake c ("Choco lava", 3.5);
}

3.

Create the Music structure, with member variables num_sold and year, and member functions sold and is_new. The sold function should print twice the num_sold while the is_new function should return true if the year is greater than 2012.

#include <iostream>
using namespace std;

// Write your code for the struct Music here.

// Write the implementation for the member functions here

int main() {
    Music m = {4, 2013};
}

Solution.

Below is one way to implement the program.

#include <iostream>
using namespace std;

struct Music {
    int num_sold;
    int year;
    void sold(int num_sold);
    bool is_new(int year);
};

void Music::sold(int num_sold) {
   cout << 2 * num_sold << endl;
}

bool Music:: is_new(int year) {
   if (year > 2012) {
     return true;
   }
   else {
     return false;
   }
}

int main() {
    Music m = {4, 2013};
}

4.

Create the Music structure, with member variables num_sold and year, and member function latest. The latest function operates on two Music objects, and returns true if the current object’s year is greater than the other’s.

#include <iostream>
using namespace std;

// Write your code for the struct Music here.

// Write the implementation for the member function latest here

int main() {
    Music m = {4, 2013};
    Music m_other = {198, 2009};
    bool is_newer = m.latest(m_other);
}

Solution.

Below is one way to implement the program.

#include <iostream>
using namespace std;

struct Music {
    int num_sold;
    int year;
    bool latest(const &Music m_other) const;
};

bool Music:: latest(const &Music m_other) const {
   if (year > m_other.year) {
     return true;
   }
   else {
     return false;
   }
}

int main() {
    Music m = {4, 2013};
    Music m_other = {198, 2009};
    bool is_newer = m.latest(m_other);
}

5.

Write the function printInfo, which prints the music album’s information in the format “This is a artist, year album with/without featured artists.” If artist has the value “n/a”, printInfo prints out “Unknown artist! Your album is from year.”

#include <iostream>
using namespace std;

struct Music {
    string artist;
    int year;
    bool has_featured;
};

// Write your code for the printInfo function here.

int main() {
    Music m1 = { "n/a", 2007, true };
    printInfo(m1);
    Cake c2 = { "Drake", 2016, false };
    printInfo(m2);
}

Solution.

Below is one way to implement the program.

#include <iostream>
using namespace std;

struct Music {
    string artist;
    int year;
    bool has_featured;
};

void printInfo(Music m) {
    if (m.artist == "n/a") {
        cout << "Unknown artist! Your album is from " << m.year << "." << endl;
    }
    else {
        if (m.has_featured == true) {
            cout << "This is a " << m.artist << ", " << m.year << " album with featured artists." << endl;
        }
        if (m.has_featured == false) {
            cout << "This is a " << m.artist << ", " << m.year << " album without featured artists." << endl;
        }
    }
}

int main() {
    Music m1 = { "n/a", 2007, true };
    printInfo(m1);
    Music m2 = { "Drake", 2016, false };
    printInfo(m2);
}

6.

The Music structure has instance variables name, weight and member function has_icing. Write the has_icing function which returns true when the weight is greater than 10.

#include <iostream>
using namespace std;

struct Cake {
    string name;
    double weight;
    bool has_icing();
};

// Write your code for the has_icing function

int main() {
     Cake c = {"Choco lava", 3.5};
}

Solution.

Below is one way to implement the program.

#include <iostream>
using namespace std;

struct Cake {
    string name;
    double weight;
    bool has_icing();
};

bool Cake::has_icing() {
     if (weight > 10) {
       return true;
     }
     else {
       return false;
     }
}

int main() {
     Cake c ("Choco lava", 3.5);
}

7.

Write the Pants structure, which has instance variables size and material. Also write a constructor for Pants that would be called when p1 is declred. The constructor sets the size to L and material to cotton.

#include <iostream>
using namespace std;

// Write your code for the struct Pants here.

// Write your code for the constructor here

int main() {
    Pants p = { 'S', "denim" };
    Pants p1;
}

Solution.

Below is one way to implement the program. We declare the Pants struct and list the instance variables in order. In addition, we write a default constructor.

#include <iostream>
using namespace std;

struct Pants {
    char size;
    string material;
    Pants();
};

Pants::Pants() {
   size = 'L';
   material = "cotton";
}

int main() {
    Pants p = { 'S', "denim" };
    Pants p1;
}

8.

Implement 2 constructors for the struct Book, which has the instance variables name and publish_year. One should be a default constructor that sets name to N/A and publish_year to 0. The other constructor should take arguments

#include <iostream>
using namespace std;

struct Book {
    string name;
    int publish_year;
    bool is_famous();
    Book();
    Book(string name_in, int publish_year_in);
};

// Write your code for the default constructor here

// Write the constructor for the argument taking constructor here

int main() {
    Book b1;
    Book b2 ("Kane and Abel", 1979);
}

Solution.

Below is one way to implement the program.

#include <iostream>
using namespace std;

struct Book {
    string name;
    int year;
    bool is_famous();
    Book();
    Book(string name_in, int publish_year_in);
};

Book::Book() {
   name = "N/A";
   publish_year = 0;
}

Book::Book(string name_in, int publish_year_in) {
   name = name_in;
   publish_year = publish_year_in ;
}

int main() {
    Book b1;
    Book b2 ("Kane and Abel", 1979);
}

9.

Implement the struct Book as would appear in the Book.h header file and the following necessary statement in main.cpp in order for thr program to run

struct Book {
    // Group and label the following as instance variables, constructors, modifiers or functions as would be seen in a header (Book.h) file
    string name;
    int publish_year;
    bool is_famous();
    Book();
    Book(string name_in, int publish_year_in);
};


#include <iostream>
using namespace std;
// Write the inclusion of the header file that is needed in main.cpp

int main() {
    Book b1;
    Book b2 ("Kane and Abel", 1979);
}

Solution.

Below is one way to implement the program.

struct Book {
    // Instance variables
    string name;
    int publish_year;
    // Functions
    bool is_famous();
    // Constructors
    Book();
    Book(string name_in, int publish_year_in);
};


#include <iostream>
using namespace std;
#include "Book.h"

int main() {
    Book b1;
    Book b2 ("Kane and Abel", 1979);
}

10.

Implement the struct Instrument struct along with 2 constructors for the same (default and one that takes parameters). Instrument has the instance variables name, year_made and function is_popular(). The default constructor sets name to guitar and year_made to 2000.

#include <iostream>
using namespace std;

// Write your struct definition and constructors here

int main() {
    Instrument first;
    Instrument second ("ukulele", 2012);
}

Solution.

Below is one way to implement the program.

#include <iostream>
using namespace std;

struct Instrument {
    string name;
    int year_made;
    bool is_popular();
    Instrument();
    Instrument(string name_in, int year_made_in);
};

Instrument::Instrument() {
   name = "guitar";
   publish_year = 2000;
}

Instrument::Instrument(string name_in, int year_made_in) {
   name = name_in;
   year_made = year_made_in;
}

int main() {
    Instrument first;
    Instrument second ("ukulele", 2012);
}

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