AP Computer Science Midterm Review

Which of the following pairs of declarations will cause an error message?

• none
• I only
• II only
• II and III only

What will be produced by the following statement?

• I
• II
• III
• none of these

The following code fragment outputs "13 / 5 = 2.0", however the programmer wanted it to output "13 / 5 = 2.6". Which of the following will NOT correct the error?

• double answer = ( double ) 13 / 5;
• double answer = 13 / ( double ) 5;
• double answer = 13.0 / 5;
• double answer = ( double ) ( 13 / 5 );

Expressions follow order of operations rules. What value will result hold after this statement is executed?

• -5
• 0
• 13
• 12

Suppose that addition and subtraction had higher precedence than multiplication and division. What would the following expression evaluate as?
(hint: Use parentheses to elevate the rank of addition and subtraction operations)

• 7
• 8
• 0
• 1

Assume aNum is a variable of type double that is positive. A program contains the boolean expression (Math.pow( aNum, 0.5 ) == Math.sqrt ( aNum )). Even though aNum^1/2 is mathematically equivalent to √aNum the above expression returns the value false in a student's program. Which of the following is the most likely reason?

• Math.pow returns an int, while Math.sqrt returns a double.
• aNum was imprecisely calculated in a previous program statement.
• The computer stores floating-point numbers with 32-bit words.
• There is round-off error in calculating the pow and sqrt functions.

If a is of type int and has a value of 0 when the segment is executed, what will happen?

• An ArithmeticException will be thrown.
• statement2, but not statement1, will be executed.
  
• statement1, but not statement2, will be executed.
  
• A syntax error will occur.

What will the output be for the following poorly formatted program segment, if the input value for x is 33?

• 33
• 3
• 3 is negative
• 33 is negative

What values are stored in num1 and num2 after execution of the following program segment?

• num1 = 30     num2 = 90
• num1 = 30     num2 = -30
• num1 = 30     num2 = 60
• num1 = 3       num2 = -3

Which of the following will evaluate to true only if boolean expressions X, Y, and Z are all false?

• !X && !( Y && !Z )
• !X || !Y || !Z
• !( X || Y || Z )
• !X || !( Y || !Z )