LESSON 166 OF 404 · PROJECTS: EVERYDAY PROGRAMS

Shopping Cart V5 - Coupon Codes in Go

Practice

Use a map as a fast lookup table for coupon discounts.

You start with:

subtotal := 100
coupon := "SAVE20"
coupons := map[string]int{"SAVE10": 10, "SAVE20": 20, "SAVE50": 50}

Build:

Total: $80

Rules:

Look up coupon in coupons. If it is there, its value is the discount; if it is not (an unknown code), the discount is 0.
total := subtotal - discount.
Build the text "Total: $<total>" (e.g. "Total: $80"; an unknown coupon would give "Total: $100").
Store it in result, then print it with fmt.Println(result).

Use discount := coupons[coupon]: Go gives the zero value (0 for an int) when the key is missing.

Use strconv.Itoa(...) to convert each number to text before concatenating it.

subtotal := 100
coupon := "SAVE20"
coupons := map[string]int{"SAVE10": 10, "SAVE20": 20, "SAVE50": 50}

discount := coupons[coupon]
total := subtotal - discount
result := "Total: $" + strconv.Itoa(total)
fmt.Println(result)

STEP 1 OF 4

Guided

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Shopping Cart V5 - Coupon Codes in Go

Shopping Cart V5 in Go