Variables in Go

Variables in Go

Variables are used to store values in a program. Go is a statically typed language, which means each variable has a specific type that cannot be changed during runtime.

Variable Declaration

There are several ways to declare variables in Go:

1. Using var keyword with explicit type

var age int
var name string
var isValid bool

2. Using var keyword with initialization

var age = 25        // type inferred as int
var name = "John"   // type inferred as string
var salary = 5000.0 // type inferred as float64

3. Short declaration using :=

age := 25        // type inferred as int
name := "John"   // type inferred as string
salary := 5000.0 // type inferred as float64

Basic Types in Go

Go has several basic types:

1. Numeric Types

   • Integers: int, int8, int16, int32, int64
   • Unsigned integers: uint, uint8, uint16, uint32, uint64
   • Floating point: float32, float64
   • Complex numbers: complex64, complex128

2. String Type

   • string

3. Boolean Type

   • bool

Multiple Variable Declarations

You can declare multiple variables in a single line:

var x, y int = 10, 20
name, age := "John", 25

Zero Values

In Go, variables declared without an explicit initial value are given their zero value:

var (
    intValue    int     // 0
    floatValue  float64 // 0.0
    boolValue   bool    // false
    stringValue string  // ""
)

Constants

Constants are declared using the const keyword:

const (
    Pi = 3.14159
    MaxValue = 100
    Greeting = "Hello"
)

Type Conversion

Go requires explicit type conversion:

var i int = 42
var f float64 = float64(i)
var u uint = uint(f)

Best Practices

1. Use short declaration (:=) inside functions
2. Use var declarations for package-level variables
3. Choose meaningful variable names
4. Use constants for values that won’t change
5. Group related variables using var blocks

Exercise

Try writing a program that:

1. Declares variables of different types
2. Performs some basic operations
3. Prints the results

Example:

package main

import "fmt"

func main() {
    // Variable declarations
    name := "Alice"
    age := 25
    height := 1.68

    // Print values
    fmt.Printf("Name: %s\n", name)
    fmt.Printf("Age: %d\n", age)
    fmt.Printf("Height: %.2f meters\n", height)
}

In the next post, we’ll explore control structures in Go, including if statements, loops, and switches!