08.arrays.go

// In Go, an array is a numbered sequence of elements of a
// specific length. In typical Go code, slices are much more
// common; arrays are useful in some special scenarios.

package main

import "fmt"

func main() {
	// Here we create an array a that will hold exactly 5 ints. The
	// type of elements and length are both of the array's
	// type. By default an array is zero-valued, which for ints
	// means 0s.
	var a [5]int
	fmt.Println("emp:", a)

	// We can set a value at an index using the array[index] =
	// value syntax, and get a value with array[index].
	a[4] = 100
	fmt.Println("set:", a)
	fmt.Println("get:", a[4])

	// The builtin len returns the length of an array.
	fmt.Println("len:", len(a))

	// Use this sintax to declare and initialize an array in one
	// line.
	b := [5]int{1, 2, 3, 4, 5}
	fmt.Println("dcl:", b)

	// You can also have the compiler count the number of
	// elements for you with ...
	b = [...]int{1, 2, 3, 4, 5}
	fmt.Println("dcl:", b)

	// If you specify the index with :, the elements in between
	// will be zeroed.
	b = [...]int{100, 3: 400, 500}
	fmt.Println("idx:", b)

	// Arrays types are one-dimensional, but you can compose
	// types to build multi-dimensional data structures.
	var twoD [2][3]int
	for i := 0; i < 2; i++ {
		for j := 0; j < 3; j++ {
			twoD[i][j] = i + j
		}
	}
	fmt.Println("2d:", twoD)

	// You can create and initialize multi-dimensional arrays at
	// once to.
	twoD = [2][3]int{
		{1, 2, 3},
		{1, 2, 3},
	}
	fmt.Println("2d:", twoD)
}