AP Comp Sci - Unit 2 Review (2.1 - 2.7)

String oldStr = "ABCDEF";

String newStr = oldStr.substring(1, 3) + oldStr.substring(4);

System.out.println(newStr);

What is printed as a result of executing the code segment?

• ABCD

• BCDE

• BCEF

• BCDEF

• ABCDEF

Consider the following method.

public double myMethod(int a, boolean b)

{  /* implementation not shown */  }

Which of the following lines of code, if located in a method in the same class as myMethod, will compile without error?

• int result = myMethod(2, false);

• int result = myMethod(2.5, true);

• double result = myMethod(0, false);

• double result = myMethod(true, 10);

• double result = myMethod(2.5, true);

String temp = "comp";

System.out.print(temp.substring(0) + " " +

temp.substring(1) + " " +

temp.substring(2) + " " +

temp.substring(3));

What is printed when the code segment is executed?

• comp

• c o m p

• comp com co c

• comp omp mp p

• comp comp comp comp

String str = "0";

str += str + 0 + 8;

System.out.println(str);

What is printed as a result of executing the code segment?

• 8

• 08

• 008

• 0008

• Nothing is printed, because numerical values cannot be added to a String object.

A student has created a Car class. The class contains variables to represent the following.

* A String variable called color to represent the color of the car

* An int variable called year to represent the year the car was made

* A String variable called make to represent the manufacturer of the car

* A String variable called model to represent the model of the car

* The object vehicle will be declared as type Car.

Which of the following descriptions is accurate?

• An instance of the vehicle class is Car.

• An instance of the Car object is vehicle.

• An attribute of the year object is int.

• An attribute of the vehicle object is color.

• An attribute of the Car instance is vehicle.

Consider the following class.

public class WindTurbine

{

private double efficiencyRating;

public WindTurbine()

{

efficiencyRating = 0.0;

}

public WindTurbine(double e)

{

efficiencyRating = e;

}

}

Which of the following code segments, when placed in a method in a class other than WindTurbine, will construct a WindTurbine object wt with an efficiencyRating of 0.25 ?

• WindTurbine wt = new WindTurbine(0.25);

• WindTurbine wt = 0.25;

• WindTurbine wt = new WindTurbine();

  wt = 0.25;

• WindTurbine wt = new WindTurbine();

  wt.efficiencyRating = 0.25;

• new WindTurbine wt = 0.25;

ExamScore class. (see Google Slide)

• 4

• 5

• 80

• 84

• 85

GameClass error (see Google Slide)

• IV only

• I and III only

• I and IV only

• II and IV only

• II, III, and IV only