initial commit

structs/structs.go

@@ -0,0 +1,58 @@
+package main
+
+import "fmt"
+// Structs are typed collections of fields.
+// they're useful for grouping data together to form records
+// the person struct type has name and age fields
+type person struct {
+	name string
+	age int
+}
+
+// newPerson constructs a new person struct with the given name
+// you can safely return a pointer to local variable as a local variable
+// will survive the scope of the func
+func newPerson(name string) *person {
+	p := person{name: name}
+	p.age = 42
+	return &p
+}
+
+func main(){
+	// This syntax creates a new struct
+	fmt.Println(person{"Bob", 20})
+	//you can name the fields when initalizing the struct
+	fmt.Println(person{name: "Alice", age: 30})
+	//omitted fields will be zero-valued
+	fmt.Println(person{name:"Fred"})
+	//an & prefix yields a pointer to the struct
+	fmt.Println(&person{name:"Ann",age: 40})
+	//its idiomatic to encapsulate new struct creation in constructor functions
+	fmt.Println(newPerson("Jon"))
+
+	//access struct fields with . notation
+	s := person{name: "Sean", age: 50}
+	fmt.Println(s.name)
+
+	// you can also use . notation with struct pointers - the pointers are
+	// automatically dereferenced
+	sp := &s
+	fmt.Println(sp.age)
+
+	// structs are mutable
+	sp.age = 51
+	fmt.Println(sp.age)
+
+	// if a struct type is only used for a single value
+	// we dont have to give it a name
+	// the value can have an anonymous struct type.
+	// this tech is used commonly in table driven tests
+	dog := struct {
+		name string
+		isGood bool
+	}{
+		"Rex",
+		true,
+	}
+	fmt.Println(dog)
+}