import cs1.Keyboard;
public class Questions
{
public static void main(String[ ] args)
{
int x, y, z;
double average;
System.out.println("Enter an integer value");
x = Keyboard.readInt( );
System.out.println("Enter another integer value");
y = Keyboard.readInt( );
System.out.println("Enter a third integer value");
z = Keyboard.readInt( );
average = (x + y + z) / 3;
System.out.println("The result of my calculation is " + average);
}
}
1) Questions computes
a) The correct average of x, y and z as a double
b) The correct average of x, y and z as an int
c) The average of x, y and z as a double, but the result may not be accurate
d) the sum of x, y and z
e) the remainder of the sum of x, y and z divided by 3
Answer: c. Explanation: Because the division is an int division, even though the result is stored in a double, the resulting double may not be accurate. For instance, if x, y and z are 1, 2 and 4, the double average should be 2.33333 but average will instead be 2.00000.
2) What is output if x = 0, y = 1 and z = 1?
a) 0
b) 0.0
c) 0.6666666666666666
d) 0.6666666666666667
e) 0.67
Answer: b. Explanation: The division is performed as an int division since x, y, z and 3 are all ints.
Therefore, average gets the value 0.0. It is output as 0.0 instead of 0 because average is a double, which outputs at least one decimal digit unless specified otherwise using the DecimalFormat class.
Java
- In Java, the mechanism that allows you to combine data and operations on the data into a single unit is called a(n)
- Which of the following is a legal way to declare and instantiate an array of 10 Strings?
- The statement System.out.println(values[7]); will
- Which of the following loops would adequately add 1 to each element stored in values?
- What is the value of values.length?
- What is returned by values[3]?
- A listener is an object that
- JOptionPane is a class that provides GUI
- In order to have some code throw an exception, you would use which of the following reserved words?
- An exception can produce a “call stack trace” which lists
- A Java program can handle an exception in several different ways. Which of the following is not a way that a Java program could handle an exception?
- Assume that you are defining a class and you want to implement an ActionListener. You state addActionListener(this); in your class’ constructor. What does this mean?
- In order to implement Comparable in a class, what method(s) must be defined in that class?
- Which of the following interfaces would be used to implement a class that represents a group (or collection) of objects?
- An object that refers to part of itself within its own methods can use which of the following reserved words to denote this relationship?
- Static methods cannot
- Which of the following methods is a static method? The class in which the method is defined is given in parentheses following the method name.
- An object may be made up of other objects.
- Method decomposition is the process of creating overloaded versions of a method that do the same thing, but operate on different data types.
- The println method on System.out is overloaded.
- A method defined without a return statement will cause a compile error.
- If a method takes a double as a parameter, you could pass it an int as the actual parameter.
- The different versions of an overloaded method are differentiated by their signatures.
- The number and types of the actual parameters must match the number and types of the formal parameters.
- The return statement must be followed a single variable that contains the value to be returned.