Java Tokens and Data types Practice Questions

Today we are going to practice short questions on Java  Tokens and Data Types. Before you attempt the questions, do a quick review of these two topics by going through our video links here.

• • • • • Java Tokens
        • Java DataTypes

1. Identify whether following are primitive or non-primitive types

(i) String  (ii) arrays  (iii) char  (iv) classes

Ans.

(i) String – Non-Primitive

(ii) arrays – Non primitive

(iii) char – Primitive

(iv) Classes – Non primitive

2. List the variables from those given below that are composite data types.

(i) static int x;

(ii) data[2] = 10;

Ans.

(i) x is of a primitive data type

(ii) data is variable of a composite or non primitive data type

3. List the variables from those given below that are composite data types.
   1. private char chr;
   2. String str;

Ans.

1. 1. chr is a variable of a primitive data type
   2. str is a variable of a composite data type – String is a class type

4. List the variables from those given below that are composite data types.
   1. display();
   2. boolean b;
   3. Scanner sc;
   4. Z = ‘\n’;

Ans.

1. 1. obj is a variable of a composite data type
   2. b is a variable of a primitive data type
   3. sc is a variable of a composite data type as Scanner is a class
   4. Z is of type char so non primitive type.

5. Arrange the following primitive data types in an ascending order of their size:

(i)         char                                                    (ii)  byte

(iii)       double                                                 (iv)  int

Ans.    byte, char, int, double

6.      (i) State the number of bytes occupied by char and int data types?

  (ii) Write one difference between / and % operator.

Ans.

(i) char occupies two bytes and  int occupied 4 bytes.

(ii) / is division operator while % is modulus operator which gives the remainder on dividing two numbers.

7. Write the size of the following integer data types in terms of bytes.
   • int
   • float
   • double
   • char

Ans.

1. 1. int: 4 bytes
   2. float: 4 bytes
   3. double: 8 bytes
   4. char: 2 bytes

8. What are the default values of the primitive data type int and float?

Ans. The default value of  int is 0 and float is 0.0F

9. Identify what is the type of literals listed below:

(i) 0.5 (ii)’A’ (iii) false (iv) “a”

Ans.

(i) Floating point literal
(ii) Character literal, single character in single quotes
(iii) Boolean literal
(iv) String literal, multiple characters in double quotes.

10. Identify the literals as given below:

i. 246 ii. ‘c’ iii. true     iv. “SimplyCoding”

Ans. i. int    ii. char     iii. boolean    iv. String

11. What is the range of the following data types:
    1. byte
    2. short
    3. long
    4. boolean

Ans:

1. 1. byte -> -128 to 127
   2. short -> -32768 to 32767
   3. long -> -2⁶³ to 2^63-1
   4. boolean – > true or false

12. Identify the literals listed below :
    • 2.5
    • ’s’
    • false
    • ”Simply”

Ans :

1. 1. Real literal
   2. character literal
   3. boolean literal
   4. String literal

13. Identify the following as valid variable names, state reason if invalid :
    • 3
    • D253
    • Emp_name
    • Salaryamount#

Ans.

1. 1. Invalid, dot (.) is not allowed.
   2. Valid
   3. Valid
   4. Invalid, # not allowed

14. Identify the following as valid variable names, state reason if invalid :
    • S%
    • _A124

Ans.

1. 1. Invalid, special character (%) not allowed.
   2. Valid _ is allowed

15. Identify the following as valid variable names, state reason if invalid :
    • _250
    • super
    • ST 106
    • While

Ans.

1. 1. valid as it begins with (underscore).
   2. Invalid, as super is a keyword.
   3. Invalid, space is not allowed.
   4. Valid, W is capital so it is not a key word.

16. Identify the following literals as character/string literals:
    • \t
    • Simply coding#?9
    • \26
    • \ r
    • \Simply

Ans.

1. 1. Character
   2. String
   3. String
   4. Character
   5. String

17. Which of the following set of values can be assigned to a boolean variable?
    • Yes and No
    • true and false
    • 0 and 1
    • high and low

Ans. b. true and false (variable Boolean can be true or false)

18. Write java statements for following:
    • Declare double variable.
    • Declare float variable and assign any value to it.
    • Declare Boolean variable and assign value to it.

Ans.

1. 1. double x;
   2. float a = 3.14;
   3. boolean r = true;

19. Predict the data type of the following:

i) int p; double q;                            ii) float m;

      r = p + q;                                           p = m/3*(Math.pow(4,3));

     Systems.out.println(r);                  System.out.println(p);

Ans. i) double ii) double

20. What is the resultant data type of the following mathematical expression?

a+b*c-d

1. where a is int, b is int, c is float and d is float type
2. where a, b, c and d are of int type, however the expression is slightly modified as

(a+b*c-d)/7.0

Ans.

1. 1. float
   2. double

21. What is the resultant data type of the following mathematical expression?

a+b*c-d

1. where a is of double and b,c and d are of int type
2. where a is char and b,c and d are of int type

Ans.

1. 1. double
   2. int

22. Identify errors in following statements and correct them:
    1. int number = 3,250;
    2. char ch = “Simply”;

Ans. correct statement:

1. 1. int number = 3250; // comma not allowed
   2. String ch = “Simply”; // char data type  can have only 1 character

23. Identify errors in following statements and correct them:
    1. int x/10 = y;
    2. int num = +25;

Ans. correct statement:

1. 1. int y= x/5;
   2. int num+ = 25;