A simple console App that can do simple CRUD (Create Read Update Delete) written in Go language

Go_SimpleConsoleApp.go

/*
Code by rkalit
*/
package main

import(
	"fmt"
	"bufio"
	"os"
)

type product struct {
	id 		int
	name 	string
	stock	int
}

var products []product

func login() bool{
	var username, password string
	fmt.Println("=============Login=============")
	fmt.Print("Username: ")
	fmt.Scan(&username)
	fmt.Print("Password: ")
	fmt.Scan(&password)

	if(username == "admin" && password == "admin"){
		fmt.Println("==========Login Succes==========")
		return true
	} else {
		fmt.Println("Incorrect Username or Password, please re-login!")
		return false
	}
}

func listMenu(){
	fmt.Println("1. Show List Product")
	fmt.Println("2. Show Product by ID")
	fmt.Println("3. Add Product")
	fmt.Println("4. Update Product")
	fmt.Println("5. Delete Product")
	fmt.Println("0. Exit")
	fmt.Print("Enter your choice: ")	
}

func menu() {
	var choose int
	listMenu()
	for {
		fmt.Scan(&choose)
		if choose == 0 {
			fmt.Println("Thank You, exiting.....")
			break
		} else {
			switch choose {
			case 1:
				showListProduct(products)
				fmt.Println("press 'Enter' to back to menu....")
				bufio.NewReader(os.Stdin).ReadBytes('\n')
				listMenu()
			case 2:
				var id int
				fmt.Println()
				fmt.Print("Enter Product ID :")
				fmt.Scan(&id)
				fmt.Println("\nInfo for Product with ID ", id)
				showProductById(id, products)
				fmt.Println("press 'Enter' to back to menu....")
				bufio.NewReader(os.Stdin).ReadBytes('\n')
				listMenu()
			case 3:
				fmt.Println("Add a new product")
				addProduct(&products)
				fmt.Println()
				fmt.Println("press 'Enter' to back to menu....")
				bufio.NewReader(os.Stdin).ReadBytes('\n')
				listMenu()
			case 4:
				var id int
				fmt.Print("Enter Product Id: ")
				fmt.Scan(&id)
				updateProductById(id, &products)
				fmt.Println()
				fmt.Println("press 'Enter' to back to menu....")
				bufio.NewReader(os.Stdin).ReadBytes('\n')
				listMenu()
			case 5:
				var id int
				fmt.Println()
				fmt.Print("Enter Product Id: ")
				fmt.Scan(&id)
				deleteProductById(id, &products)
				fmt.Println()
				fmt.Println("press 'Enter' to back to menu....")
				bufio.NewReader(os.Stdin).ReadBytes('\n')
				listMenu()
			default:
				fmt.Println("Re-enter your choice!")
				listMenu()
			}
		}
	}			
}

/*** Start of CRUD Function***/

func showListProduct(products []product) {
	// Untuk setiap product p dengan index i pada array products
	for _, p := range products {
		fmt.Println("ID	:", p.id)
		fmt.Println("Name	:", p.name)
		fmt.Println("Stock	:", p.stock)
		fmt.Println()
	}
}


func showProductById(id int, products []product) {
	for _, p := range products {
		if p.id == id {
			fmt.Println("ID	:", p.id)
			fmt.Println("Name	:", p.name)
			fmt.Println("Stock	:",p.stock)
			fmt.Println()
		}
	}
}

func addProduct(products *[]product) {
	var id int
	consoleReader := bufio.NewReader(os.Stdin)
	var stock int
	fmt.Println()
	fmt.Print("Enter Product Id : ")
	fmt.Scan(&id)
	fmt.Print("Enter Product Name : ")
	name, _ := consoleReader.ReadString('\n') //accept the whitespace
	fmt.Print("Enter Product Stock : ")
	fmt.Scan(&stock)

	product_ := product{id, name, stock}

	*products = append(*products, product_)
}

func updateProductById(id int, products *[]product) {
	var newStock int
	fmt.Println()
	fmt.Print("Enter the New quantity of the Product: ")
	fmt.Scan(&newStock)

	for i, p := range *products {
		if p.id == id {
			(*products)[i] = product{id, p.name, newStock}
		}
	}
}

func deleteProductById(id int, products *[]product) {
	for i, p := range *products {
		if p.id == id {
			*products = append((*products)[:i], (*products)[i+1:]...)
		}
	}
}

/*** End of CRUD Function ***/

func DitenunApp() {
	for !login() {
		login()
		break
	}
	// Example data
	products = append(products, product{id : 1, name : "Ulos 1", stock: 25})
	products = append(products, product{id : 2, name : "Ulos 2", stock: 15})
	
	menu()
}

func main() {
	DitenunApp()
}