Go language interfaces are different from other languages. In Go language, the interface is a custom type that is used to specify a set of one or more method signatures and the interface is abstract, so you are not allowed to create an instance of the interface. But you are allowed to create a variable of an interface type and this variable can be assigned with a concrete type value that has the methods the interface requires. Or in other words, the interface is a collection of methods as well as it is a custom type. To read more about Interfaces, please refer to the article Interface in Golang
There are two structures and one interface. One structure is for gfg course details and another structure is for contest details. One interface is having get_name method which will return names of course and contest. With the help of the interface, we will access the structure’s variable as we don’t want to access the structure’s variable from outside.
Example 1: This program will take 2 inputs.
// Golang program to access the interface fields package main
import "fmt"
// Declare course structure type Course struct {
name string
} // Declare contest structure type Contest struct {
name string
} // Declare interface type Name interface {
get_name() string
} // get_name function for course func (a Course) get_name() string {
return a.name
} // get_name function for contest func (b Contest) get_name() string {
return b.name
} // Compare course and contest name. // Name is interface type func name_compare(course, contest Name) bool {
return contest.get_name() == course.get_name();
} func main() {
var course_name, contest_name string
// Get the course name from user
fmt.Println( "Enter course name: " )
fmt.Scan(&course_name)
// Get the contest's name from user
fmt.Println( "Enter contest name: " )
fmt.Scan(&contest_name)
// Create structure of course
course := Course{course_name}
// Create structure of contest
contest := Contest{contest_name}
fmt.Print( "Is same subjects in course and contest: " )
// Call interface function to compare names
fmt.Print(name_compare(course, contest))
} |
Output:
Enter course name: DBMS Enter contest name: DBMS Is same subjects in course and contest: true
Example 2: This program will take 2 inputs.
// Golang program to access the interface fields package main
import "fmt"
// Declare courseprice structure type Courseprice struct {
price int
} // Declare contestprice structure type Couponprice struct {
price int
} // Declare interface type Price interface {
get_price() int
} // get_price function for Courseprice func (a Courseprice) get_price() int {
return a.price
} // get_price function for Coupon price func (b Couponprice) get_price() int {
return b.price
} // Compare courseprice and Couponprice. // Price is interface type func price_compare(courseprice, Couponprice Price) bool {
if courseprice.get_price() <= Couponprice.get_price() {
return true
} else {
return false
}
} func main() {
var courseprice, Couponprice int
// Get the courseprice from user
fmt.Println( "Enter course price: " )
fmt.Scan(&courseprice)
// Get the Couponprice from user
fmt.Println( "Enter Coupon Price: " )
fmt.Scan(&Couponprice)
// Create structure of courseprice
course := Courseprice{courseprice}
// Create structure of Couponprice
Coupon := Couponprice{Couponprice}
fmt.Print( "Is the course is free: " )
// Call interface function to compare price
fmt.Print(price_compare(course, Coupon))
} |
Output:
Enter course price: 1000 Enter Coupon Price: 700 Is the course is free: false