Question on Character and Boolean Data Types

Question on Character and Boolean Data Types

1. What is the numerical range of a char data type in Java?

a) -128 to 127

b) 0 to 256

c) 0 to 32767

d) 0 to 65535

Answer: d

Explanation: Char occupies 16-bit in memory, so it supports 2^16 i:e from 0 to 65535.

2. Which of these coding types is used for data type characters in Java?

a) ASCII

b) ISO-LATIN-1

c) UNICODE

d) None of the mentioned

Answer: c

Explanation: Unicode defines fully international character set that can represent all the characters found in all human languages. Its range is from 0 to 65536.

3. Which of these values can a boolean variable contain?

a) True & False

b) 0 & 1

c) Any integer value

d) true

Answer: a

Explanation: Boolean variable can contain only one of two possible values, true and false.

4. Which of these occupy first 0 to 127 in Unicode character set used for characters in Java?

a) ASCII

b) ISO-LATIN-1

c) None of the mentioned

d) ASCII and ISO-LATIN1

Answer: d

Explanation: First 0 to 127 character set in Unicode are same as those of ISO-LATIN-1 and ASCII.

5. Which one is a valid declaration of a boolean?

a) boolean b1 = 1;

b) boolean b2 = ‘false’;

c) boolean b3 = false;

d) boolean b4 = ‘true’

Answer: c

Explanation: Boolean can only be assigned true or false literals.

6. What is the output of this program?

    class array_output {

        public static void main(String args[])

        {   

            char array_variable [] = new char[10];

                for (int i = 0; i < 10; ++i) {

                array_variable[i] = 'i';

                System.out.print(array_variable[i] + "" );

                i++;

            }

        }

    }

a) i i i i i

b) 0 1 2 3 4

c) i j k l m

d) None of the mentioned

Answer: a

Explanation: None.

output:

$ javac array_output.java

$ java array_output

i i i i i

7. What is the output of this program?

    class mainclass {

        public static void main(String args[])

        {

            char a = 'A';

            a++;

                System.out.print((int)a);

        }

    }

a) 66

b) 67

c) 65

d) 64

Answer: a

Explanation: ASCII value of ‘A’ is 65, on using ++ operator character value increments by one.

output:

$ javac mainclass.java

$ java mainclass

66

8. What is the output of this program?

class mainclass {

        public static void main(String args[])

        {

            boolean var1 = true;

                boolean var2 = false;

                if (var1)

                    System.out.println(var1);

                else

                    System.out.println(var2);

       }

    }

a) 0

b) 1

c) true

d) false

Answer: c

Explanation: None.

output:

$ javac mainclass.java

$ java mainclass

true

9. What is the output of this program?

    class booloperators {

        public static void main(String args[])

        {

            boolean var1 = true;

                boolean var2 = false;

                System.out.println((var1 & var2));

        }

    }

a) 0

b) 1

c) true

d) false

Answer: d

Explanation: boolean ‘&’ operator always returns true or false. var1 is defined true and var2 is defined false hence their ‘&’ operator result is false.

output:

$ javac booloperators.java

$ java booloperators

false

10. What is the output of this program?

    class asciicodes {

        public static void main(String args[])

        {

            char var1 = 'A';

                char var2 = 'a';

                System.out.println((int)var1 + " " + (int)var2);

        }

    }

a) 162

b) 65 97

c) 67 95

d) 66 98

Answer: b

Explanation: ASCII code for ‘A’ is 65 and for ‘a’ is 97.

output:

$ javac asciicodes.java

$ java asciicodes

65 97