MED Update Balance

Textio needs a new way to update user's account balance.

Assignment

Implement the updateBalance function. It should take a customer pointer and a transaction, and return an error. Depending on the transactionType, it should either add or subtract the amount from the customer's balance. If the customer does not have enough money, it should return the error insufficient funds. If the transactionType isn't a withdrawal or deposit, it should return the error unknown transaction type. Otherwise, it should process the transaction and return nil.

alice := customer{id: 1, balance: 100.0}
deposit := transaction{customerID: 1, amount: 50, transactionType: transactionDeposit}

updateBalance(&alice, deposit)
// id: 1 balance: 150

Solution

main.go

package main

import (
	"errors"
)

type customer struct {
	id      int
	balance float64
}

type transactionType string

const (
	transactionDeposit    transactionType = "deposit"
	transactionWithdrawal transactionType = "withdrawal"
)

type transaction struct {
	customerID      int
	amount          float64
	transactionType transactionType
}

// Don't touch above this line

func updateBalance(c *customer, t transaction) error{
	
	
	if t.transactionType == "deposit"{
		c.balance += t.amount
		return nil
	}
	if t.transactionType == "withdrawal"{
		if t.amount <= c.balance{
			c.balance-=t.amount
			return nil
		}else if t.amount > c.balance{
			return errors.New("insufficient funds")
		}
	}

	return errors.New("unknown transaction type")
}