Golang CLI Compiler Online
A simple, CLI-based tool to run and test Go code in real time without local setup.
π‘ Learn Go to upgrade your skills
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π‘ Go Basics Guide for Beginners
1. Declaring Variables and Constants
Use var
or :=
to declare variables. Use const
for constants.
package main
var x int = 10
const Pi = 3.14
func main() {
name := "Alice"
isActive := true
println(x, Pi, name, isActive)
}
2. Conditionals (if / switch)
Go supports if-else
and switch
statements with clean syntax.
x := 2
if x == 1 {
println("One")
} else if x == 2 {
println("Two")
} else {
println("Other")
}
switch x {
case 1:
println("One")
case 2:
println("Two")
default:
println("Other")
}
3. Loops
Go uses only the for
loop, but it can act like a while loop.
for i := 0; i < 3; i++ {
println(i)
}
n := 3
for n > 0 {
println(n)
n--
}
4. Arrays
Arrays have fixed size. Use slices for dynamic lists.
var nums = [3]int{10, 20, 30}
println(nums[1])
5. Slice Manipulation
Use slices and the built-in append
, len
, copy
, and slicing syntax.
fruits := []string{"apple", "banana"}
fruits = append(fruits, "cherry")
fruits = fruits[1:] // slice
println(len(fruits))
for _, fruit := range fruits {
println(fruit)
}
6. Console Input/Output
Use fmt.Print
, fmt.Scan
, and fmt.Println
.
import "fmt"
var name string
fmt.Print("Enter your name: ")
fmt.Scan(&name)
fmt.Println("Hello", name)
7. Functions
Functions are declared with func
and can return multiple values.
func greet(name string) string {
return "Hello, " + name
}
message := greet("Alice")
println(message)
8. Maps
Maps are key-value stores. Declare with make()
.
ages := map[string]int{"Alice": 30}
ages["Bob"] = 25
println(ages["Alice"])
9. Error Handling
Go uses multiple return values for errors instead of exceptions.
import "errors"
func fail() error {
return errors.New("something went wrong")
}
err := fail()
if err != nil {
println(err.Error())
}
10. File I/O
Use os
and io/ioutil
packages to read/write files.
import (
"fmt"
"os"
"io/ioutil"
)
ioutil.WriteFile("file.txt", []byte("Hello File"), 0644)
data, _ := ioutil.ReadFile("file.txt")
fmt.Println(string(data))
11. String Manipulation
Use the strings
package for string operations.
import "strings"
text := " Hello World "
println(strings.TrimSpace(text))
println(strings.ToUpper(text))
println(strings.ReplaceAll(text, "Hello", "Hi"))
words := strings.Split(text, " ")
fmt.Println(words)
12. Structs & Objects
Use structs to define custom types with methods.
type Person struct {
Name string
}
func (p Person) Greet() string {
return "Hi, I'm " + p.Name
}
p := Person{Name: "Alice"}
println(p.Greet())
13. References (Pointers)
Go supports pointers using *
and &
.
x := 10
ptr := &x
*ptr = 20
println(x) // 20