Page 147 - ComputerScience_Class_11

6.8 CLASS AS MECHANISM FOR USER-DEFINED TYPE
A Java program is made up of classes and each class contains attributes (data members) that are predefined data types.
While creating an object of a class, we are basically defining a variable whose size is determined by the total bytes of
these predefined data types. A user-defined data type is a derived data type that depends on some existing data types.
Therefore, a class acts as a mechanism for creating user-defined data types.

Let’s Revisit

♦ Every individual component used in Java code is known as a Token. It is also known as the building block of Java Programs.
♦ Identifiers are user-defined names required to name a class, variables or a method.
♦ Values that are stored in the variables are known as literals.
♦ Punctuators are the special characters that have some special jobs.
♦ Separators are special characters in Java, which are used to separate the variable or the character.
♦ Operators use operands to perform mathematical and non-mathematical operations to give some results.
♦ An escape sequence is a non-graphical character preceded by a backslash (\) having a special meaning for the compiler.
♦ There are two different types of data: primitive and non-primitive.
♦ In Java, there are eight different types of primitive data and four types of non-primitive data.
♦ Arithmetic expressions contain variables, constants and arithmetic operators and are used to do calculations.
♦ The process of changing the value of one type to another type is known as type conversion or type casting. There are two
different types of conversions: implicit and explicit.
♦ The wrapper class is used to convert the primitive data type to its object and vice versa. Each primitive data type has a wrapper
class of its own.

MIND DRILL

Solved Questions

A. Tick ( ) the correct option.
1. What is a named memory location where a value is being stored?
a. Separator b. Variable
c. Data type d. Sum
2. int a=5;
What is “a” in the above code?
a. Punctuator b. String
c. Identifier d. Literal
3. What type of operator "?:" is?
a. Shift b. Bitwise
c. Logical d. Ternary

4. What is the use of "\n"?
a. Inserts a carriage return b. Inserts a vertical tab
c. Inserts a new line d. Inserts a backspcae

Primitive Values, Wrapper Classes, Types and Casting 145