APCSA Unit 3 Review

Consider the code segment below

What is printed as a result?

int x = 10;

int y = 20;

System.out.print(y + x / y);

• 1

• 1.5

• 3

• 20

• 20.5

Answer explanation

ORDER OF OPERATIONS!!!

Division (INTEGER DIVISION) happens FIRST!

Which of the following expressions evaluates to 1?

1. 2 / 5 % 3

2. 2 / (5 % 3)

3. 2 / 5 + 1

• 1 only

• 2 only

• 1 and 2 only

• 2 and 3 only

• 1, 2, and 3

Answer explanation

Divided by (/) and mod (%) have the same level of importance, so without parentheses we do them from left to right

Consider the following:

int a = 2;

int b = 6;

int c = 3;

Which of the following expressions evaluates to false?

• a < b == c < b

• a > b == b < c

• a < b != c < b

• a < b != c < b

Consider the following code segment

boolean a = true;

boolean b = true;

System.out.print((b || (!a || b)) + " ");

System.out.print(((!b || !a) && a) + " ");

System.out.println(!(a && b) && b);

• true false false

• true true true

• true false true

• false true false

Consider the following code segment.

String str1 = new String("Happy");

String str2 = new String("Happy");

System.out.print(str1.equals(str2) + " ");

System.out.print(str2.equals(str1) + " ");

System.out.print(str1 == str2);

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

• true true true

• true true false

• false true false

• false false true

Consider the following code segment, which is intended to store the sum of all multiples of 10 between 10 and 100, inclusive (10 + 20 + ... + 100), in the variable total.

int x = 100;

int total = 0;

while( /* missing code */ )

{

total = total + x;

x = x - 10;

}

Which of the following can be used as a replacement for /* missing code */ so that the code segment works as intended?

• x < 100

• x <= 100

• x > 10

• x >= 10

Consider the following code segment.

int a = 1;

String result = "";

while (a < 20)

{

result += a;

a += 5;

}

System.out.println(result);

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

• 21

• 161116

• 161161

• Nothing is printing because of an infinite loop.

Consider the following code segment.

int count = 0;

int number = 20;

while (number > 0)

{

number = number / 2;

count++;

}

What will be the value of count after executing the code segment?

• 6

• 5

• 4

• 1

Consider the following code segment.

String word = "Computer";

int num = 3;

String result = "";

 

for (int k = num; k >= 0; k--)

{

   result += word.substring(0, k);

}

 

System.out.print(result);

 

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

• comcoc

• ccocom

• ccocomcomp

• comcomcomcom

Consider the following code segment.

int a = 100;

while (a > 1)

{

System.out.println("$");

a /= 2;

}

How many $’s are printed as a result of executing the code segment?

• 0

• 5

• 6

• 7

• 50