[Go]Interface assignment 2

This is an assignment 2 about interface from the course Go: The Complete Developer’s Guide (Golang) by Stephen Grider, this topic is difficult to understand but Stephen explained it well.

Below is the code for the assignment2. So the purpose of interface in golang is to try to reduce the code, while golang is not OOP hence there is no inheritance.

On this assignment2 I need to create a type shape interface which includes the printArea() float64 which prints out the area of any shapes.

While interface only defines the signature of the function, the implementation under the receiver’s function has to be defined by yourself hence interface cannot check if your implementation is correct or not but it is trying to standardize the argument and the output of the function.

So below is the code for the assignment 2.

package main

import "fmt"

type square struct {
	sideLength float64

type triangle struct {
	base float64
	height float64

type shape interface {
	printArea() float64

func main() {
	sq := square{6.5}
	tri := triangle{height: 4.5, base: 3.5}

func getArea(sh shape) {

func (sqr square) printArea() float64 {
	return sqr.sideLength * sqr.sideLength

func (tr triangle) printArea() float64 {
	return 0.5 * tr.base * tr.height

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