A variable is a storage location that holds a value. The set of permissible values is determined by the variable's type.
Java language has primitive types and objects, and both have different syntax to declare a variable.
Primitive type variable:
int a
String b
float c
Object type variable:
Java is object oriented language so that we can have access modifier for variable declaration:
In Java we can declare variables in many places like Local variable, Parameters, Class level, Instance variable.
Animal a = new Animal()
Student s = new Student()private int a
public String b
protected float c
private Animal a Variable Naming
- Variable names are case-sensitive
- An unlimited-length sequence of Unicode letters and digits
- Beginning with a letter, the dollar sign "$", or the underscore character "_".
- No special characters allowd as identifier of variable
- We can't use reserved keywords
package main
import "fmt"
func main() {
var x int // Line 1
x = 10 // Line 2
var y string = "Hello Go!" // Line 3
fmt.Println(x)
fmt.Println(y)
}In Line 1, var indicate it's a variable, x is the name of variable and int is the type of variable.
In Line 2, we are assigning the value in x variable.
In Line 3, we have declared a string variable and assigned in single line
Since creating a new variable with a starting value is so common Go also supports a shorter statement:
y := "Hello Go!"
With the above shorter syntax Go compiler will automatically identify that y is a variable of type string and its value is "Hello Go!".
Declare multiple variable at same time:
var (
name string
age int
location string
)-
Inside Function
-
Out Side Function.
Function / Local Variable
package main
import "fmt"
func main(){
var x int = 10
fmt.Println(x)
}
Global Variable
package main
import "fmt"
func main(){
var x int = 10
fmt.Println(x)
}Any function can access the y variable, while x is local variable only accessible inside the main function.
package main
import "fmt"
var y int =10
func main(){
var x int = 10
fmt.Println(x)
fmt.Println(y)
}
func hello(){
fmt.Println(y)
}
Variable Names
package main
import "fmt"
var y int =10
func main(){
var x int = 10
fmt.Println(x)
fmt.Println(y)
}
func hello(){
fmt.Println(y)
}Name must be start with letter
Name may contain letter, number and underscore (_)
Name is character sensetive Num and num consider as two different variable
{{ parent.title || parent.header.title}}
{{ parent.tldr }}
{{ parent.linkDescription }}
{{ parent.urlSource.name }}