Variables, Types and Packages

var age int = 25nvar price float64 = 19.99nname := "Tutoline"       // short declaration -- type is inferrednisActive := true

Go is statically typed like Java or C++, but the := short declaration operator infers the type automatically, similar in feel to auto in C++ or var in JavaScript — you will use := for the large majority of variable declarations inside a function.

Common types

• int, int64 — whole numbers
• float64 — decimal numbers
• string — text
• bool — true/false

Every declared variable must be used

func main() {n    unused := 5n    // Error: unused is declared and not usedn}

This surprises newcomers coming from other languages — Go’s compiler refuses to build code with an unused local variable, treating it as a near-certain mistake rather than a harmless warning. It feels strict at first, but it genuinely does catch real bugs (like a variable you meant to use but forgot to).

Packages and imports

import (n    "fmt"n    "strings"n)nnfunc main() {n    upper := strings.ToUpper("tutoline")n    fmt.Println(upper)n}

Go organizes code into packages, and the standard library covers an enormous amount of everyday functionality — strings, strconv (type conversion), net/http (a full HTTP server, no framework required), and many more, all included with the language itself.

Exported vs unexported names

A function or variable starting with a capital letter (like fmt.Println) is exported — visible to code outside its package. A lowercase name is unexported — private to its own package. This single naming convention replaces the separate public/private keywords you would find in Java or C++.