Variables in Go Programming Language

Variable declaration using var keyword

we can declare variables in Golang using var keyword like below

var name string
var address string
var age int

we can also declare multiple variables with single keyword like below

var(
 name string
 address string
 age int
)

var(
 name, address string
 age int
)

Example program

package main
import "fmt"

func main() {
  
  var(
    name string
    age int
    address string
    weight float64
    height float32
    isHeayWeight bool
    )
    
    fmt.Printf("name:%s,age:%d,address:%s,weight:%f,height:%f,isHeayWeight:%t \n",
    name,age,address,weight,height,isHeayWeight)
	
}

You can run this program live here https://onecompiler.com/go/3usz2cqnz

Output

name:,age:0,address:,weight:0.000000,height:0.000000,isHeayWeight:false 

Type Interface

In Golang we do not mention the type of the variable explicitly, based on value it infers the type of the variable

var name = "onecompiler"

basing on above declaration it infers the type of name variable to String.
If we changes the value from string to number it will throw compilation error.

var name ="onecompiler" //infers string type
name = 1234 //throws compilation error

Type inference allows us to declare and initialise multiple variables of different data types in a single line.

Example

package main
import "fmt"

func main() {
	// Multiple variable declarations with inferred types
    var name, address, age, salary = "OneCompiler", "Hyderabad", 28, 50000.0

    fmt.Printf("name: %T, address: %T, age: %T, salary: %T\n", 
        name, address, age, salary)
        fmt.Printf("name: %s, address: %s, age: %d, salary: %f\n", 
        name, address, age, salary)

}

You can run this program live here https://onecompiler.com/go/3usz35ua4

Output

name: string, address: string, age: int, salary: float64
name: OneCompiler, address: Hyderabad, age: 28, salary: 50000.000000

Short Declaration

we can declare variables shortly in Golang using := operator

Example

package main
import "fmt"
func main() {
	// Short variable declaration syntax
	name := "OneCompiler"
	age, salary, isExcellentSite := 35, 50000.0, true

	fmt.Println(name, age, salary, isExcellentSite)
}

Output

OneCompiler 35 50000 true