Practice Go right here — no installs, no signups.
Go was designed at Google for services that must be simple to read and fast to build. It compiles in a blink, has garbage collection, and makes concurrency a first-class language feature through goroutines and channels. This online Go compiler runs your package main directly.
Practise slices and maps, structs and methods, interfaces, error returns as ordinary values, and concurrency with go func and channels. Go's compiler is strict — unused variables and imports are hard errors, which trains tidy code fast.
Copy any snippet into the editor above and press Run. Each one is short on purpose — retype it from memory afterwards.
package main
import "fmt"
type Student struct {
Name string
Marks int
}
func (s Student) Passed() bool { return s.Marks >= 40 }
func main() {
s := Student{"Aarav", 78}
fmt.Println(s.Name, "passed:", s.Passed())
}Methods hang off a receiver (s Student) rather than living inside the type body.
package main
import "fmt"
func main() {
ch := make(chan string)
go func() { ch <- "from a goroutine" }()
fmt.Println(<-ch)
}Receiving from an unbuffered channel blocks until the goroutine sends — that is how the program stays in sync.
declared and not used
Why: Go rejects unused local variables.
Fix: Remove the variable or assign it to _ if it is intentionally ignored.
imported and not used
Why: An import is present but never referenced.
Fix: Delete the import line.
all goroutines are asleep - deadlock!
Why: Every goroutine is blocked on a channel with no sender or receiver.
Fix: Make sure something sends before you receive, or use a buffered channel.
| Concept | Syntax |
|---|---|
| Package + main | package main\nfunc main() { } |
| fmt.Println(x) | |
| Slice | nums := []int{1, 2, 3} |
| Map | m := map[string]int{"a": 1} |
| Error return | v, err := doThing() |
| Goroutine | go worker() |
No. Single-file package main snippets run as-is here.
Yes, the program runs on a real Go runtime, so scheduling and channel semantics behave normally.
Running snippets builds speed; the 17-chapter course builds understanding. Work through the Go chapters, take the quiz, then claim your certificate.
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