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Practice Test 1 Computer Science I

Question 1. (15 points) Suppose we have the following declarations:

int m, n, i = 3, j = 4, k = 5;

double v, w, x = 2.8, y = 5.0;

final int p = 2;

Determine the value assigned to the variable in each of the following assignment statements or explain why it is not a valid assignment.

a) m = 1 + k / 2 + i % 2;

b) n = (int) x * 3.0 + 6;

c) v = p * y + k;

d) w = j / i + k;

e) m = 5 * x - (k % 2);

f) p = 2 * (int)0 x + k + j;

g) n = j * k + (int) x;

Question 2. (10 points) Write a Java statement to calculate the following formula, where x, y, z are variables of type double.

Hints: Use Math.sqrt( ) to calculate the square root (e.g, Math.sqrt(9.0) returns 3.0)

Use Math.pow( ) to calculate the power (e.g., Math.pow(2.0, 3.0) returns 8.0)

y = z +

Question 3. (10 points) Based on the value of the "percentageOfTuitionIncrease" variable, write nested-if statements that prints the appropriate messages in a Text object.

Tuition Increase Range	Message to Print
percentageOfTuitionIncrease £ 1	"Great!"
1 < percentageOfTuitionIncrease < 4	"Reasonable"
4 £ percentageOfTuitionIncrease £ 8	"Tolerable"
8 < percentageOfTuitionIncrease	"Outrageous!"

Question 4. (10 points) Show the exact output generated by the below code:

int i = 50, j = 60, k, m;

new Text( i + j + "= Sum", 10, 50, canvas);

new Text( "Sum = " + i + j, 10, 100, canvas);

new Text( "Sum = " + (i + j), 10, 150, canvas );

canvas

Question 5. (40 points) Suppose we have the following two Java files:

ProductTester.java

Product.java

public class ProductTester {

public static void main (String[ ] args) {

double x, y, total;

total = 123.0;

Product p1 = new Product("gum", 3, 1.00);

Product p2 = new Product("corn",8, 2.50);

x = p1.doSomething(4);

y = p2.doSomething(2);

p1 = p2;

} // end main

} // end ProductTester

public class Product {

private String name;

private int groupCount;

private double priceForGroup;

public Product (String name, int group,

double price) {

this.name = name;

groupCount = group;

priceForGroup = price;

} // end Product

public double doSomething(int g) {

double total;

total = g*priceForGroup;

return total;

} // end totalCost

} // end class Product

a) At the end of the "main" method of ProductTester, what would be the value of the following:

total:

p1.groupCount:

p2.groupCount:

b) Write a new method for the Product class called "grossCost" that returns the cost of a gross of the product. A gross is defined to be 12 dozen or 144 units.

c) Write a statement for the ProductTester to determine the cost of a gross of Product p1 using your "grossCost" method.

d) On the code at the top of the page, label one of each of the following: an instance variable, a parameter, a local variable, a Product object, a return type, an instantiable class.

Question 6. (10 points) Below is the template for a class that extends WindowController. The begin method draws a FramedRect with a Text object with the word "HI!". You are to add the code to allow the user to drag both of these with the mouse.

import objectdraw.*;

import java.awt.*;



public class T1_Q6 extends WindowController {



// Instance variables

private FramedRect box;

private Text message;









public void begin() {

box = new FramedRect(100, 100, 50, 50, canvas);

Text message = new Text("HI!", 115, 115, canvas);











} // end begin



public void onMouseClick(Location point) {











} // end onMouseClick



public void onMousePress(Location point) {













} // end onMousePress



public void onMouseRelease(Location point) {













} // end onMouseRelease



public void onMouseDrag(Location point) {













} // end on MouseDrag

} // end T1_Q6 class

Question 7. (5 points) What type of values make good named constants (using "final") in a program?