Inheritance means inheriting the properties of the superclass into the base class and is one of the most important concepts in Object-Oriented Programming. Since Golang does not support classes, so inheritance takes place through struct embedding. We cannot directly extend structs but rather use a concept called composition where the struct is used to form other objects. So, you can say there is No Inheritance Concept in Golang.
In composition, base structs can be embedded into a child struct and the methods of the base struct can be directly called on the child struct as shown in the following example.
Example 1:
// Golang program to illustrate the // concept of inheritance package main import ( "fmt"
) // declaring a struct type Comic struct {
// declaring struct variable
Universe string
} // function to return the // universe of the comic func (comic Comic) ComicUniverse() string { // returns comic universe
return comic.Universe
} // declaring a struct type Marvel struct {
// anonymous field,
// this is composition where
// the struct is embedded
Comic
} // declaring a struct type DC struct {
// anonymous field
Comic
} // main function func main() { // creating an instance
c1 := Marvel{
// child struct can directly
// access base struct variables
Comic{
Universe: "MCU" ,
},
}
// child struct can directly
// access base struct methods
// printing base method using child
fmt.Println( "Universe is:" , c1.ComicUniverse())
c2 := DC{
Comic{
Universe : "DC" ,
},
}
// printing base method using child
fmt.Println( "Universe is:" , c2.ComicUniverse())
} |
Output:
Universe is: MCU Universe is: DC
Multiple inheritances take place when the child struct is able to access multiple properties, fields, and methods of more than one base struct. Here the child struct embeds all the base structs as shown through the following code:
Example 2:
// Golang program to illustrate the // concept of multiple inheritances package main import ( "fmt"
) // declaring first // base struct type first struct {
// declaring struct variable
base_one string
} // declaring second // base struct type second struct {
// declaring struct variable
base_two string
} // function to return // first struct variable func (f first) printBase1() string{ // returns a string
// of first struct
return f.base_one
} // function to return // second struct variable func (s second) printBase2() string{ // returns a string
// of first struct
return s.base_two
} // child struct which // embeds both base structs type child struct {
// anonymous fields,
// struct embedding
// of multiple structs
first
second
} // main function func main() { // declaring an instance
// of child struct
c1 := child{
// child struct can directly
// access base struct variables
first{
base_one: "In base struct 1." ,
},
second{
base_two: "\nIn base struct 2.\n" ,
},
}
// child struct can directly
// access base struct methods
// printing base method
// using instance of child struct
fmt.Println(c1.printBase1())
fmt.Println(c1.printBase2())
} |
Output:
In base struct 1. In base struct 2.