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The Way to Go

Solution Review: Make a Simple Interface

Understand how to create a simple interface in Go by defining method signatures and implementing them with pointer receiver methods on a struct. Explore how to use this interface in functions and test it with practical examples.

We'll cover the following...
Go (1.6.2)
package main
import (
	"fmt"
)
type Simpler interface {  // interface implementing functions called on Simple struct
	Get() int
	Set(int)
}
type Simple struct {
	i int
}
func (p *Simple) Get() int {
	return p.i
}
func (p *Simple) Set(u int) {
	p.i = u
}
func fI(it Simpler) int {     // function calling both methods through interface
	it.Set(5)
	return it.Get()
}
func main() {
	var s Simple
	fmt.Println(fI(&s))  // &s is required because Get() is defined with a receiver type pointer
}

In the code above, from line 6 to line 9, we define the interface Simpler by specifying the signature of the functions Get and Set. The Get() function returns an integer, and the Set(int) function takes an integer as a parameter. Note that because these are only function descriptions, we do not have to specify variables’ names here.

The type Simple itself is defined ...