Starting out with C++ : from control structures through objects

Answers for C++ Course using "Starting out with C++ : from control structures through objects" by Tony Gaddis. 7/8th ed. I used the Pearson myprogramminglab to complete the homework. Here are my solutions/answers for the exercises/labs so please use the test bank as a GUIDE if you're stuck. Let me know if you find a better solution to a problem or any of the programming challenges. Thanks in advance for your support! Send in missing programming challenges to cplusplus.answers@gmail.com

13.5 Focus on Software Engineering: Separating Class Specification from Implementation: 10896

Question

Write the interface (.h file) of a class GasTank containing:
A data member named amount of type double.
A data member named capacity of type double.
A constructor that accepts a parameter of type double.
A function named addGas that accepts a parameter of type double and returns no value.
A function named useGas that accepts a parameter of type double and returns no value.
A function named isEmpty that accepts no parameters and returns a boolean value.
A function named isFull that accepts no parameters and returns a boolean value.
A function named getGasLevel that accepts no parameters and returns a double.
A function named fillUp that accepts no parameters and returns a double.

Solution
class GasTank
{
    private:
        double amount;
        double capacity;

    public:
        GasTank(double);
        void addGas(double);
        void useGas(double);
        bool isEmpty();
        bool isFull();
        double getGasLevel();
        double fillUp();
};

13.5 Focus on Software Engineering: Separating Class Specification from Implementation: 10889

Question

Write the implementation (.cpp file) of the Averager class of the previous exercise. The full specification of the class is:
An data member named sum of type integer.
An data member named count of type integer.
A constructor with no parameters. The constructor initializes the data members sum and the data member count to 0.
A function named getSum that accepts no parameters and returns an integer. getSum returns the value of sum .
A function named add that accepts an integer parameter and returns no value. add increases the value of sum by the value of the parameter, and increments the value of count by one.
A function named getCount that accepts no parameters and returns an integer. getCount returns the value of the count data member, that is, the number of values added to sum .
A function named getAverage that accepts no parameters and returns a double. getAverage returns the average of the values added to sum . The value returned should be a value of type double (and therefore you must cast the data members to double prior to performing the division).

Solution
Averager::Averager()
{
    sum=0;
    count=0;
}

int Averager::getSum()
{
    return sum;
}

void Averager::add(int theNum)
{
    sum+=theNum;
    count++;
}

int Averager::getCount()
{
    return count;
}

double Averager::getAverage()
{
    return (double) sum / (double) count;
}

13.5 Focus on Software Engineering: Separating Class Specification from Implementation: 10885

Question

Write the implementation (.cpp file) of the Accumulator class of the previous exercise. The full specification of the class is:
An data member named sum of type integer.
A constructor that accepts no parameters. The constructor initializes the data member sum to 0.
A function named getSum that accepts no parameters and returns an integer. getSum returns the value of sum .
A function named add that accepts an integer parameter and returns no value. add increases the value of sum by the value of the parameter.

Solution
Accumulator::Accumulator()
{
    sum=0;
}

int Accumulator::getSum()
{
    return sum;
}

void Accumulator::add(int theNum)
{
    sum+=theNum;
}

13.5 Focus on Software Engineering: Separating Class Specification from Implementation: 10877

Question

Write the implementation (.cpp file) of the Counter class of the previous exercise. The full specification of the class is:
A data member counter of type int .
An data member named limit of type int .
A static int data member named nCounters which is initialized to 0 .
A constructor that takes two int arguments and assigns the first one to counter and the second one to limit . It also adds one to the static variable nCounters
A function called increment that accepts no parameters and returns no value. If the data member counter is less than limit , increment just adds one to the instance variable counter .
A function called decrement that accepts no parameters and returns no value. If counter is greater than zero, decrement subtracts one from the counter .
A function called getValue that accepts no parameters. It returns the value of the instance variable counter .
A static function named getNCounters that accepts no parameters and return an int . getNCounters returns the value of the static variable nCounters .

Solution
int Counter::nCounters = 0;

Counter::Counter(int theCounter, int theLimit)
{
        nCounters++;
        counter = theCounter;
        limit=theLimit;
}

void Counter::increment()
{
    if (counter<limit)
        counter++;
}

void Counter::decrement()
{
    if (counter>0)
        counter--;
}

int Counter::getValue()
{
    return counter;
}

int Counter::getNCounters()
{
    return nCounters;
}

13.5 Focus on Software Engineering: Separating Class Specification from Implementation: 10854

Question

Write the interface (.h file) of a class Counter containing:
An instance variable counter of type int , initialized to 0.
A function called increment that adds one to the instance variable counter . It does not accept parameters or return a value.
A function called getValue that doesn't accept any parameters. It returns the value of the instance variable counter .
A default constructor.

Solution
class Counter {

private:
int counter;

public:
void increment();
int getValue();
Counter();
};

13.5 Focus on Software Engineering: Separating Class Specification from Implementation: 10853

Question

Write the implementation (.cpp file) of the ContestResult class from the previous exercise. Again, the class contains:
An instance variable winner of type string , initialized to the empty string.
An instance variable secondPlace of type string , initialized to the empty string.
An instance variable thirdPlace of type String , initialized to the empty string.
A function called setWinner that has one parameter, whose value it assigns to the instance variable winner .
A function called setSecondPlace that has one parameter, whose value it assigns to the instance variable secondPlace .
A function called setThirdPlace that has one parameter, whose value it assigns to the instance variable thirdPlace .
A function called getWinner that has no parameters and that returns the value of the instance variable winner .
A function called getSecondPlace that has no parameters and that returns the value of the instance variable secondPlace .
A function called getThirdPlace that has no parameters and that returns the value of the instance variable thirdPlace .

Solution
void ContestResult::setWinner (string theWinner)
{
    winner = theWinner;
}

void ContestResult::setSecondPlace (string theSecondPlace)
{
    secondPlace = theSecondPlace;
}

void ContestResult::setThirdPlace (string theThirdPlace)
{
    thirdPlace = theThirdPlace;
}

string ContestResult::getWinner ()
{
    return winner;
}

string ContestResult::getSecondPlace()
{
    return secondPlace;
}

string ContestResult::getThirdPlace()
{
    return thirdPlace;
}

13.3: Defining an Instance of a Class in C++: 11204

Question

Creating objects of the Currency class require a name (string), a currency symbol (string) and the number of decimal places (integer) usually associated with the currency (in that order). Creating objects of the Money class require a Currency object, and the actual amount (integer) (in that order). Define an object of type Currency named canadianDollars and corresponding to the name "Canadian Dollar", the symbol "C$", and 2 decimal places. Define an object of type Money named valueInCanadians corresponding to 230 units of canadianDollars.

Solution
Currency canadianDollars ("Canadian Dollar", "C$", 2);
Money valueInCanadians (canadianDollars,230);

13.3: Defining an Instance of a Class in C++: 11200

Question

Objects of the Window class require a width (integer) and a height (integer) be specified (in that order) upon definition. Declare two integers corresponding to a width and a length and read values into them from standard input (in that order). Use these value to define an object of type Window named newWindow.

Solution
int width, length;
cin >> width >> length;
Window newWindow (width, length);

13.3: Defining an Instance of a Class in C++: 11198

Question

Objects of the Window class require a width (integer) and a height (integer) be specified (in that order) upon definition. Define an object named window, of type Window, corresponding to a 80 x 20 window.

Solution
Window window (80,20);

13.3: Defining an Instance of a Class in C++: 11196

Question

Objects of the BankAccount class require a name (string) and a social security number (string) be specified (in that order)upon creation. Define an object named account , of type BankAccount , using the values "John Smith" and "123-45-6789" as the name and social security number respectively.

Solution
BankAccount account ("John Smith", "123-45-6789");

CH12: Programming Challenge #15

Question
I only have a partial...anyone have more info send via comment.

SC-CUSTOM EXERCISE

12.9: Random-Access Files with C++

I don't have the questions, if you have them send via comment.

12.3: Passing File Stream Objects to Functions in C++ 11319

Question

Write the definition of a function named openLog . This function can be safely passed two arguments, an fstream object and a string object. The function associates the fstream with a file whose name is formed by concatenating the second argument with the suffix ".log". The fstream is made ready for output that is appended to the end of the file. If the file did not exist previously, false is returned; otherwise its content is deleted (truncated) and replaced by a single line:
PREVIOUS CONTENT DELETED
and true is returned.

Solution
If you have a solution, please send via comment

12.2: File Output Formatting: 11308

Question

Given three variables, k, m, n, of type int that have already been declared and initialized, write some code that prints each of them left-justified in a 9-position field on the same line. For example, if their values were 27, 987654321, -4321, the output would be:

|27xxxxxxx987654321-4321xxxx

NOTE: The vertical bar, | , on the left above represents the left edge of the print area; it is not to be printed out. Also, we show x in the output above to represent spaces-- your output should not actually have x's!

Solution
cout.setf(ios::left, ios::adjustfield);
cout << setw(9) << k << setw(9) << m << setw(9) << n;

12.2: File Output Formatting: 11304

Question

Given three variables, a, b, c, of type double that have already been declared and initialized, write a statement that prints each of them on the same line, separated by one space, in such away that scientific (or e-notation or exponential notation) is avoided. Each number should be printed with 5 digits to the right of the decimal point. For example, if their values were 4.014268319, 14309, 0.00937608, the output would be:

|4.01427x14309.00000x0.00938

NOTE: The vertical bar, | , on the left above represents the left edge of the print area; it is not to be printed out. Also, we show x in the output above to represent spaces-- your output should not actually have x's!

Solution
cout << setprecision(5);
cout << fixed << a << " " << b << " " << c << " ";