What is a closure in Go?

Closure in Go is a function that "remembers" values from its surrounding scope even after the outer function has finished. This allows capturing variables from outside and using them inside.

// Outer function
func makeCounter() func() int {
    count := 0 // Variable to be captured

    // Inner function (closure)
    return func() int {
        count++ // Capture and modify count
        return count
    }
}

// Usage example
func main() {
    counter1 := makeCounter() // Create first closure
    fmt.Println(counter1()) // Output: 1
    fmt.Println(counter1()) // Output: 2

    counter2 := makeCounter() // Create second closure (with its own count)
    fmt.Println(counter2()) // Output: 1
}