3. Go - Pointer Basics

Pointer is a reference to a memory, or an address to something saved in memory. 

Could use pointers to reference big data stored in memory to save time and efficiency. Could also use pointers to change values outside of scopes.

Example Code:

// creating a variable that returns a pointer

package main

import "fmt"

var pointervar *int // This is a pointer type with int

func main() {

    variable := "string"

    intvar := 50

    pointervar = &intvar

    var x int = MathAdd(&variable)

    fmt.Println(variable)

    fmt.Println(x)

    fmt.Println(*pointervar)

}

func MathAdd(p *string) int {

    *p = "toy"

    return 5

}

* = pointer to a type/variable, the value that is stored at address

& = address of a type/variable where its stored

*& = dereference the value stored at the address

var b = new(int)

// this creates a variable integer that also returns a pointer. can reference pointer b with "&b"

Dereferencing Pointer Slices:

// must dereference the slice type first with (*VARIABLE)

// then can access indexs

Example:

package main

import "fmt"

type myArray []int

func (list *myArray) removeValue(x int) {

    for i := 0; i < len(*list); i++ {

        fmt.Println(i)

        if (*list)[i] == x {

            *list = append((*list)[:i], (*list)[(i+1):]...)

            return

        }

    }

}

func main() {

    x := myArray{1, 2, 3, 4, 5}

    fmt.Println(x)

    x.removeValue(2)

    fmt.Println(x)

}