practice_final.md

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title: Practice Final

The final exam will be a closed-book paper exam without a calculator. Exam questions will be similar in type to those found here, but fewer in number. While this practice exam is a good study guide, we highly recommend being familiar with all the material (including but not limited to your previous exams, labs, projects, quizzes and homework) as well.

Problem 0 (Warm-up)

#. What is the escape sequence for a new line? #. What is the return type of a constructor? #. List 4 datatypes. #. What is the difference between a variable and a constant? #. In an exam class, if I want to keep track of the total number of exams should the attribute be static or non-static? #. Write a condition that evaluates to true if an int length is between 4 and 16, both inclusive. #. Write a statement or statements that creates an int array of size 50 with each index containing that index as its value. (i.e. 0 at [0], 13 at [13], 49 at [49], etc.). #. Write a statement or statements to create a random number generator called examRand and use it to generate a random number between 40 and 57 (inclusive).

Problem 1

Consider the code below:

class VirtualPet{
    private string name = "Blank";          // Name of the pet.
    private decimal hungerLevel = 1m;       // Level of hunger, with 1 being full, in percent.
    private decimal happinessLevel = 1m;    // Level of happiness, in percent

    public void SetName(string nameP)
    {
        name = nameP;
    }
}

#. Write a statement to instantiate a VirtualPet object called firstPet.

#. Write a getter for the name attribute.

#. Write a setter for the hungerLevel attribute that takes one decimal. The argument should be assigned to the hungerLevel attribute only if it is between 0 and 1 (both included), otherwise the attribute should get the value 0.

#. Draw the UML diagram for the VirtualPet class, including the methods you just added.

#. Write a constructor that takes 3 arguments (string, decimal, decimal) for the VirtualPet class. Your constructor should be such that if one of the decimal arguments is not between 0 and 1 (both included), then 0 gets assigned to both decimal attributes.

#. Your earlier statement that created the firstPet object will no longer compile after you add the constructor. Why is this the case?

#. Write a ToString method for the VirtualPet class. It should display the name, hungerLevel, and happinessLevel. (Bonus) Display hungerLevel and happinessLevel graphically: for instance, if hungerLevel is at 4.5, display "Hunger: XXXX". You may freely use symbols as if they were normal letters.

#. Write a statement that would use the ToString method from the VirtualPet class you just added to display information about the secondPet object.

Problem 2

This question will have you partially design, implement and use class to represent hamburgers. A Burger has a name, a price, a Boolean for dairy, and a type (typically beef, pork, chicken, veggie).

#. Draw the UML diagram for the Burger class, assuming it contains the listed attributes, a getter for the name attribute and a setter for the price attribute. Do not include any other methods.

#. Write a setter for the price attribute.

#. Write an additional constructor that takes a name, a dairy, and a type. The price should then be set according to the following table. If the value for type is not in the table, price should be set to -99.99.

#. Write a static method Promotion that takes as an argument a price and returns a value 75% of the argument.

#. Write a ToString method. The string returned should contain the values of all attributes.

Problem 3

Complete the table based on the code.

---

x y z Displays

---

-1 'e' 18.2M

-1 'a' -2

0 'c' 4.6M

1 'd' 2

-1 'b' 115

1 'd' -33.7M

0 'a' 0

1 'c' 13

                                                5

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int x;
char y;
decimal z;

// x, y, and z are given legal values

if(x<0 && y == 'a'){
  Console.Write("1");
}
else if(z%2==0){
  Console.Write("2");
}
else if(y=='c' || y=='d'){
  Console.Write("3");
}
else if(x!=0 && z!=0){
  Console.Write("4");
}
else{
  Console.Write("5");
}

Problem 4

Given two int arrays of equal length, write a code segment that compares the values at each index to see if they match. Return the total number of matches.

Problem 5 (Deceptively hard)

Given two string arrays (array A and array B) of unknown (possibly different) lengths, determine if there are any values found in both A and B. If they exist, display them to the screen. At the end of the program, display the total number of common values between A and B. If there are repeating values in either or both arrays, each should only be counted once.

(Bonus): How could Lists be used to make this problem easier?

Problem 6

Write a program that declares an int variable called "pin" and asks the user for their pin. As long as the user enters something that is not a number, is negative, or greater than 9999, your program should ask again.

(Bonus): Your code should make sure that the pin has exactly 4 digits, including leading zeros.

Problem 7

#. Write a statement that would create an int array of size 100.

#. Write a series of statements that would ask the user to enter a value for each cell in the array (no need to perform user-input validation, but you may if you like). #. Write a series of statements that would ask the user to enter a value, displaying "In your array" if the value is in your array. #. Write a series of statements that would display the sum of values in the array. #. Write a series of statements that would display the product of all the non-zero values in the array. #. Write a series of statements that would display the smallest index of the greatest value in the array.