Data Types
1. Primitive data types - includes byte, short, int, long, float, double, boolean and char
2. Non-primitive data types - such as String, Arrays and Classes.
Primitive Data Types
Non-Primitive Data Types
Difference between Primitive and Non-primitive:
- Data Type is used to store different types of values in variables.
- Example
- int myNum = 5; // Integer (whole number)
- float myFloatNum = 5.99f; // Floating point number
- char myLetter = 'D'; // Character
- boolean myBool = true; // Boolean
- String myText = "Hello"; // String
- Data types are divided into two groups:
1. Primitive data types - includes byte, short, int, long, float, double, boolean and char
2. Non-primitive data types - such as String, Arrays and Classes.
Primitive Data Types
- A primitive data type specifies the size and type of variable values, and it has no additional methods.
- Numbers
- Primitive number types are divided into two groups:
- (a) Integer types stores whole numbers, positive or negative (such as 123 or -456), without decimals.
- Example: byte, short, int and long.
- (b) Floating-point types represents numbers with a fractional part, containing one or more decimals.
- Example: float and double.
- 1. Byte:
- Syntax: byte variable_name;
- Example: byte myNum = 100;
- System.out.println(myNum);
- Characteristics:
- Size: 1 byte
- Capacity: Stores whole numbers from -128 to 127
- 2. Short:
- Syntax: short variable_name;
- Example: short myNum = 5000;
- Syste.out.println(myNum);
- Charateristics:
- Size: 2byte
- Capacity: Stores whole numbers from -32,768 to 32,767
- 3. Int:
- Syntax: int variable_name;
- Example: int myNum = 100000;
- System.out.println(myNum);
- Characteristics:
- Size: 4 byte
- Capacity: Stores whole numbers from -2,147,483,648 to 2,147,483,647
- 4. Long:
- Syntax: long variable_name;
- Example: long myNum = 15000000000L;
- System.out.println(myNum);
- Characteristics:
- Define: It is write at end the value with an "L":
- Size: 8 byte
- Capacity: Stores whole numbers from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
- 5. Float:
- Syntax: float variable_name;
- Example: float myNum = 5.75f;
- System.out.println(myNum);
- Characteristics:
- Define: It is write at end the value with an "f":
- Size: 4 byte
- Capacity: Stores fractional numbers. Sufficient for storing 6 to 7 decimal digits
- 6. Double:
- Syntax: double variable_name;
- Example: double myNum = 19.99d;
- System.out.println(myNum);
- Characteristics:
- Define: It is write at the end the value with a "d":
- Size: 8 byte
- Capacity: Stores fractional numbers. Sufficient for storing 15 decimal digits
- 7. Boolean:
- Syntax: boolean variable_name;
- Example: boolean bl = True;
- System.out.println(bl);
- Characteristics:
- Size: 1 bit
- Capacity: Stores true or false values
- 8. Char:
- Syntax: char variable_name;
- Example: char c;
- Characteristics:
- Define:
- The character must be surrounded by single quotes, like 'A' or 'C' or 'S':
- You can use ASCII values to display certain characters. such as a=65 or b=66
- Size: 2 byte
- Capacity: Stores a single character/letter or ASCII values
Non-Primitive Data Types
- String:
- Strings are used for storing text.
- A String variable contains a collection of characters surrounded by double-quotes.
- Syntax: String variable_name = "value";
- Example: String greeting = "Hello";
- Array:
- Arrays are used to store multiple values in a single variable, instead of declaring separate variables for each value.
- To declare an array, define the variable type with square brackets:
- Syntax: datatype variable_name[];
- Syntax: datatype []variable_name;
- Example: int age[];
- Example: int []age;
- Class:
- Everything in Java is associated with classes and objects.
- A Class is like an object constructor or a "blueprint" for creating objects.
- To create a class, use the keyword class.
- Syntax:
- public class Class_name {
- }
- Example:
- public class MyClass {
- }
Difference between Primitive and Non-primitive:
- Primitive types are predefined (already defined) in Java.
- Non-primitive types are created by the programmer and is not defined by Java (except for String).
- non-primitive types can be used to call methods to perform certain operations, while primitive types cannot.
- A primitive type has always a value, while non-primitive types can be null.
- A primitive type starts with a lowercase letter, while non-primitive types start with an uppercase letter.
- The size of a primitive type depends on the data type, while non-primitive types have all the same size
Tags:
Core java