Differences

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--- programming:go [2023/09/04 14:15] – skipidar
+++ programming:go [2023/11/01 07:31] (current) – ↷ Page moved from camunda:programming:go to programming:go skipidar
@@ Line 148: / Line 148: @@
 }
 </sxh>
+== Variables ==
+The ''':=''' short variable assignment operator indicates that short variable declaration is being used. There is no need to use the var keyword or declare the variable type.
+<sxh go>
+package main
+import (
+	"fmt"
+	"github.com/jboursiquot/proverbs"
+	"strconv"
+)
+// package variables
+var x, y, z bool = true, true, true
+// accesses the package level values
+func packlvlvars() (bool, bool, bool) {
+	return x, y, z
+}
+func main() {
+	// method variables
+	// below vars are covering the package-level values in the scope of current function
+	// long variant
+	// split declaration and assignment
+	var mvar int
+	mvar = 123
+	fmt.Println(mvar)
+	// combine declaration and assignment
+	var mvar2 int = 123
+	fmt.Println(mvar2)
+	// declare multiple
+	x, y, z := 1, 2, "bla"
+	fmt.Println(strconv.Itoa(x) + strconv.Itoa(y) + z)
+	// need a special value to get package variables
+	a, b, c := packlvlvars()
+	fmt.Println(strconv.FormatBool(a) + strconv.FormatBool(b) + strconv.FormatBool(c))
+}
+</sxh>
+== Pointers ==
+<sxh go>
+// basic-types/pointers/end/main.go
+package main
+import (
+	"fmt"
+	"reflect"
+)
+func main() {
+	// create a variable of type *T where T is an int
+	var a *int
+	// declare and assign `b` variable of type int
+	valu := 100
+	// assign the address of b to a
+	pointr = &valu
+	// print out the value of a which is the address of b
+	fmt.Println(pointr)
+	// returns: ptr
+	fmt.Println("Type: %s", reflect.ValueOf(pointr).Kind() )
+	// print out the value at the address of b
+	fmt.Println(*pointr)
+}
+</sxh>
+== Structs & pass by reference or value ==
+Structure to hold data in Go Lang
+<sxh go>
+type author struct {
+	first string
+	last  string
+}
+// getter
+// attention - the assignment to struct - is derived from parenthesis after "func" keyword
+// is declared OUTSIDE of struct :(
+func (a author) fullName() string {
+	return a.first + " " + a.last
+}
+// setter
+// passing the reference, so that we change the exact object and not its value
+// changeName changes the first and last name of the author
+func (a *author) changeName(first, last string) {
+	a.first = first
+	a.last = last
+}
+func main() {
+	// initialize author
+	a := author{
+		first: "Marcus",
+		last:  "Aurelius",
+	}
+	// print the author's full name
+	fmt.Println(a.fullName())
+}
+</sxh>
+''*address'' - passes by reference
+Explains why to pass
+{{https://s3.eu-central-1.amazonaws.com/alf-digital-wiki-pics/sharex/lzCAcBclf3.png?529x226}}