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Chapter 4 · Week 4

Operators, Expressions, and Type Conversion

Key concepts Practice 39

Answered 0/39 Correct 0

All Not answered Got wrong Multiple choice Short answer Programming ⚡ Quick quiz (10)

What is the value of 17 / 5 in Java?

A 3 B 3.4 C 4 D 3.0

What is the value of 17 % 5?

A 2 B 3 C 3.4 D 0

What is the value of -17 / 5?

A −4 B −3 C −3.4 D 3

What is the value of -17 % 5?

A 2 B −2 C 3 D −3

What does 17.0 / 5 evaluate to?

A 3 B 3.4 C 3.0 D It does not compile.

What is the value of 2 + 3 * 4 - 6 / 3?

A 18 B 12 C 6 D 14

What is the value of 10 % 3 * 2?

A 0 B 2 C 1 D 6

Which expression correctly computes the average of two int variables a and b as a double?

A (a + b) / 2 B (double)(a + b) / 2 C (double)((a + b) / 2) D a + b / 2.0

What is the output?

int i = 5;
int j = i++;
System.out.print(i + " " + j);

A 5 5 B 6 5 C 6 6 D 5 6

Q10

What is the output?

int i = 5;
int j = ++i;
System.out.print(i + " " + j);

A 5 5 B 6 5 C 6 6 D 5 6

Q11

What is the value of x after int x = 5; x = x++;?

A 4 B 5 C 6 D It does not compile.

Q12

What is the output?

int a = 3;
System.out.print(a++ + ++a);

A 6 B 7 C 8 D 9

Q13

What is the result of compiling and executing the following?

public class Question6 {
    public static void main(String[] args) {
        int meal = 2;
        int tip  = 4;
        int total = meal + (meal > 1 ? ++tip : --tip);
        System.out.println(tip);
    }
}

A 1 B 2 C 3 D 5

Q14

In the previous question, what is the value of total?

A 5 B 6 C 7 D 8

Q15

Which line does not compile?

byte b = 10;   // L1
b += 5;        // L2
b = b + 5;     // L3
b++;           // L4

A L1 B L2 C L3 D L4

Q16

x *= 2 + 3; is equivalent to:

A x = x * 2 + 3; B x = x * (2 + 3); C x = (x * 2) + 3; D x = 2 + 3;

Q17

Which sequence shows the widening primitive conversions in the correct order?

A int → short → long → double B byte → short → int → long → float → double C double → float → int D char → byte → int

Q18

Why does short c = a + b; fail to compile when a and b are short?

A short values cannot be added. B The operands are promoted to int, and an int cannot be assigned to a short without a cast. C short is not a primitive type. D Only final variables may be added.

Q19

What is the value of (int) 9.99?

A 9 B 10 C 9.0 D It does not compile.

Q20

What is the value of (int) -9.99?

A −10 B −9 C −9.0 D It does not compile.

Q21

What does the following print?

System.out.println('a' + 1);

A a1 B b C 98 D It does not compile.

Q22

What does the following print?

System.out.println((char)('a' + 1));

A a1 B b C 98 D It does not compile.

Q23

Which cast is illegal in Java?

A (int) 'A' B (char) 66 C (int) true D (double) 5

Q24

What is printed by System.out.println(1 + 2 + "3" + 4 + 5);?

A 3345 B 12345 C 3 345 D 15

Q25

What is printed by System.out.println("" + 1 + 2 * 3);?

A 123 B 16 C 9 D 36

Q26

What happens at run time when an int is divided by zero?

A The result is Infinity. B An ArithmeticException is thrown. C The result is 0. D The code does not compile.

Q27

What is the value of 5.0 / 0?

A 0.0 B Infinity C NaN D An exception is thrown.

Q28

Why is if (0.1 + 0.2 == 0.3) false?

A Java evaluates the sum left to right. B Floating-point values are stored as binary approximations. C == cannot be used with numbers. D The sum is computed as an int.

Q29

What does n % 2 == 0 test?

A That n is positive B That n is even C That n is odd D That n is zero

Q30

What is the value of max after int a = 4, b = 9; int max = (a > b) ? a : b;?

A 4 B 9 C true D It does not compile.

Q31

In the conditional expression cond ? x++ : y++, how many of x and y are incremented?

A Both B Only the one in the selected branch C Neither D It does not compile.

Q32

What is the output?

int total = 0;
for (int i = 1; i <= 3; i++) {
    total += i * i;
}
System.out.print(total);

A 6 B 9 C 14 D 36

Q33

Which expression is equivalent to !(a > b) for numeric a and b?

A a < b B a <= b C a >= b D a != b

Q34

What is the result of int x = (int)(7 / 2.0);?

A 3 B 3.5 C 4 D It does not compile.

Q35

An int variable holding 2147483647 is incremented by 1. What happens?

A A compile-time error. B An ArithmeticException. C The value wraps around to −2147483648. D The value stays at 2147483647.

Q36 Short answer

Explain, with one line of code each, the difference between (double)(sum / count) and (double) sum / count when sum and count are both int.

Q37 Short answer

Why does b += 5 compile for a byte while b = b + 5 does not? Write the statement that the compiler effectively generates.

Q38 Short answer

Trace int x = 2; int y = x++ * --x + x--; step by step and give the final values of x and y.

Q39 Programming

Write a program SecondsConverter that stores a total number of seconds (for example 9265) in an int and prints it in the form 2 h 34 min 25 s, using only integer division and the remainder operator.

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