Calculating the Total Cost

Part of the Logic & Flow section of Coddy's Dart journey — lesson 35 of 65.

Challenge

Easy

Create a program that continues the shopping cart calculator project by implementing the functionality to calculate the total cost of all items in the shopping cart. Building on the previous lesson's cart management, your program should:

Use the existing product catalog Map and populated shopping cart List from the previous setup
Read multiple string inputs representing items that customers want to add to their cart (the input will end when you receive "cart_done")
For each item, check if it exists in the product catalog using containsKey()
If the item exists, add it to the shopping cart List using the add() method
Calculate the total cost by iterating through the cart list and looking up each item's price in the product map
Sum up all the prices to get the final total cost
Display the cart calculation report in the exact format shown below

For example, if the store has products "Apple" at 1.50, "Banana" at 0.80, "Orange" at 2.00, "Milk" at 3.25, and customers want to add "Apple", "Banana", "Apple", "Milk", your program should output:

Shopping Cart Operations:
Adding 'Apple': Item added to cart successfully
Adding 'Banana': Item added to cart successfully
Adding 'Apple': Item added to cart successfully
Adding 'Milk': Item added to cart successfully
Cart Contents: [Apple, Banana, Apple, Milk]
Cost Calculation:
Apple: $1.50
Banana: $0.80
Apple: $1.50
Milk: $3.25
Total Cost: $7.05
Cart Summary:
Total items in cart: 4
Unique products in cart: 3
Items successfully added: 4
Items not found: 0
Cart Status: Ready for checkout

If the store has products "Laptop" at 999.99, "Mouse" at 25.50, "Keyboard" at 75.00, and customers want to add "Mouse", "Keyboard", "Mouse", "Monitor", your program should output:

Shopping Cart Operations:
Adding 'Mouse': Item added to cart successfully
Adding 'Keyboard': Item added to cart successfully
Adding 'Mouse': Item added to cart successfully
Adding 'Monitor': Item not available in store
Cart Contents: [Mouse, Keyboard, Mouse]
Cost Calculation:
Mouse: $25.50
Keyboard: $75.00
Mouse: $25.50
Total Cost: $126.00
Cart Summary:
Total items in cart: 3
Unique products in cart: 2
Items successfully added: 3
Items not found: 1
Cart Status: Ready for checkout

If the store has products "Novel" at 12.99, "Magazine" at 4.50, "Textbook" at 89.00, and customers want to add "Novel", "Magazine", "Novel", "Textbook", "Dictionary", your program should output:

Shopping Cart Operations:
Adding 'Novel': Item added to cart successfully
Adding 'Magazine': Item added to cart successfully
Adding 'Novel': Item added to cart successfully
Adding 'Textbook': Item added to cart successfully
Adding 'Dictionary': Item not available in store
Cart Contents: [Novel, Magazine, Novel, Textbook]
Cost Calculation:
Novel: $12.99
Magazine: $4.50
Novel: $12.99
Textbook: $89.00
Total Cost: $119.48
Cart Summary:
Total items in cart: 4
Unique products in cart: 3
Items successfully added: 4
Items not found: 1
Cart Status: Ready for checkout

Your program must iterate through each item in the shopping cart list, look up its price in the product catalog map, and add that price to a running total. Use a loop to process each cart item and accumulate the total cost. Display each item's individual price during the cost calculation phase. Format all prices to show exactly 2 decimal places. The input format will be: item names to add to the cart, ending with "cart_done".

Try it yourself

import 'dart:io';

void main() {
  // Product catalog with items and prices
  Map<String, double> productCatalog = {
    'Apple': 1.50,
    'Banana': 0.80,
    'Orange': 2.00,
    'Milk': 3.25,
    'Laptop': 999.99,
    'Mouse': 25.50,
    'Keyboard': 75.00,
    'Novel': 12.99,
    'Magazine': 4.50,
    'Textbook': 89.00
  };
  
  // Shopping cart to store selected items
  List<String> shoppingCart = [];
  
  // Counters for tracking operations
  int successfulAdditions = 0;
  int itemsNotFound = 0;
  
  print("Shopping Cart Operations:");
  
  // Read items until "cart_done" is received
  String? item;
  while ((item = stdin.readLineSync()) != "cart_done") {
    if (item != null) {
      if (productCatalog.containsKey(item)) {
        shoppingCart.add(item);
        successfulAdditions++;
        print("Adding '$item': Item added to cart successfully");
      } else {
        itemsNotFound++;
        print("Adding '$item': Item not available in store");
      }
    }
  }
  
  // Display cart contents
  print("Cart Contents: $shoppingCart");
  
  // Calculate unique products
  Set<String> uniqueProducts = shoppingCart.toSet();
  
  // Display cart summary
  print("Cart Summary:");
  print("Total items in cart: ${shoppingCart.length}");
  print("Unique products in cart: ${uniqueProducts.length}");
  print("Items successfully added: $successfulAdditions");
  print("Items not found: $itemsNotFound");
  print("Cart Status: Ready for checkout");
}