Questions on Integer and Floating Data Types

Questions on Integer and Floating Data Types

1. What is the range of short data type in Java?

a) -128 to 127

b) -32768 to 32767

c) -2147483648 to 2147483647

d) None of the mentioned

Answer: b

Explanation: Short occupies 16 bits in memory. Its range is from -32768 to 32767.

2. What is the range of byte data type in Java?

a) -128 to 127

b) -32768 to 32767

c) -2147483648 to 2147483647

d) None of the mentioned

Answer: a

Explanation: Byte occupies 8 bits in memory. Its range is from -128 to 127.

3. Which of the following are legal lines of Java code?

   1. int w = (int)888.8;

   2. byte x = (byte)100L;

   3. long y = (byte)100;

   4. byte z = (byte)100L;

a) 1 and 2

b) 2 and 3

c) 3 and 4

d) All statements are correct

Answer: d

Explanation: Statements (1), (2), (3), and (4) are correct. (1) is correct because when a floating-point number (a double in this case) is cast to an int, it simply loses the digits after the decimal. (2) and (4) are correct because a long can be cast into a byte. If the long is over 127, it loses its most significant (leftmost) bits. (3) actually works, even though a cast is not necessary, because a long can store a byte.

4. An expression involving byte, int, and literal numbers is promoted to which of these?

a) int

b) long

c) byte

d) float

Answer: a

Explanation: An expression involving bytes, ints, shorts, literal numbers, the entire expression is promoted to int before any calculation is done.

5. Which of these literals can be contained in float data type variable?

a) -1.7e+308

b) -3.4e+038

c) +1.7e+308

d) -3.4e+050

Answer: b

Explanation: Range of float data type is -(3.4e38) To +(3.4e38)

6. Which data type value is returned by all transcendental math functions?

a) int

b) float

c) double

d) long

Answer: c

Explanation: None.

7. What is the output of this program?

    class average {

        public static void main(String args[])

        {

            double num[] = {5.5, 10.1, 11, 12.8, 56.9, 2.5};

            double result;

            result = 0;

            for (int i = 0; i < 6; ++i)

                result = result + num[i];

                System.out.print(result/6);

        }

    }

a) 16.34

b) 16.566666644

c) 16.46666666666667

d) 16.46666666666666

Answer: c

Explanation: None.

output:

16.46666666666667

8. What will be the output of these statement?

class output {

        public static void main(String args[])

        {

            double a, b,c;

            a = 3.0/0;

            b = 0/4.0;

            c=0/0.0;

                System.out.println(a);

            System.out.println(b);

            System.out.println(c);

        }

    }

a) Infinity

b) 0.0

c) NaN

d) all of the mentioned

Answer: d

Explanation: For floating point literals, we have constant value to represent (10/0.0) infinity either positive or negative and also have NaN (not a number for undefined like 0/0.0), but for the integral type, we don’t have any constant that’s why we get an arithmetic exception.

9. What is the output of this program?

    class increment {

        public static void main(String args[])

        {       

             int g = 3;

             System.out.print(++g * 8);

        }

    }

a) 25

b) 24

c) 32

d) 33

Answer: c

Explanation: Operator ++ has more preference than *, thus g becomes 4 and when multiplied by 8 gives 32.

output:

$ javac increment.java

$ java increment

32

10. What is the output of this program?

    class area {

        public static void main(String args[])

        {   

             double r, pi, a;

             r = 9.8;

             pi = 3.14;

             a = pi * r * r;

             System.out.println(a);

        }

    }

a) 301.5656

b) 301

c) 301.56

d) 301.56560000

Answer: a

Explanation: None.

output:

$ javac area.java

$ java area

301.5656