B4 - Increment, Decrement, and Assignment Operators

What is the most common operation performed by a program?

• Adding integer one to an integer variable.

• Floating point division.

• Object construction.

• Internet access.

What two steps are performed when an assignment statement is executed?

• 1. The expression on the right of the "=" is evaluated, "using" all the variables it contains.
  2. The result of evaluation is assigned to the variable on the left of the "=".
• 1. All appropriate variables are incremented or decremented.
  2. The result is assigned to the variable on the left of the "=".
• 1. All appropriate variables are incremented.
  2. All appropriate variables are decremented.
• 1. The arithmetic expression is evaluated and assigned to the variable on the left of the "=".
  2. Variables are auto-incremented or auto-decremented.

What is the meaning of variable++ ?

• Add one to the variable.

• Add one to the variable after its current value has been used.

• Add one to the variable before using its value.

• Double the value in the variable.

What does the following program output to the monitor:

int value = 0;

int count = 1;

value = count++ ;

System.out.println("value: "+ value " + count: " + count );

• value: 0 count: 0

• value: 0 count: 1

• value: 1 count: 1

• value: 1 count: 2

What does the following program output to the monitor:

int value = 0;

int count = 1;

value = ++ count ; /* note change from previous */

System.out.println("value: "+ value " + count: " + count );

• value: 0 count: 1

• value: 1 count: 1

• value: 1 count: 2

• value: 2 count: 2

What is the output of the following:

int a = 0;

int b = 10;

a = --b ;

System.out.println("a: " + a + " b: " + b );

• a: 9 b:11

• a: 10 b: 9

• a: 9 b:9

• a: 0 b:9

What is the output of the following program:

double w = 12.5 ;

w *= 2 ;

System.out.println( " w is " + w );

• w is 12.5

• w is 13.5

• w is 25.0

• w is 2

Which of the answers does the same thing as the following:

value += sum++ ;

• value = value + sum;

  sum = sum + 1;

• sum = sum + 1;

  value = value + sum;

• value = value + sum;

• value = value + ++sum;

Fill in the blank so that wages is divided by two.

wages _____ 2 ;

• *=

• -=

• =/

• /=

Are the auto-increment and auto-decrement operators (++ and -- ) an essential part of the Java language?

• No—any program that uses them could be written without them.

• No—they are not fundamental, but some programs could not be written without them.

• Yes—some programs can't be written unless these operators are available.

• Yes—because adding or subtracting one can't be done without them.