Purpose

Gain programming experience with Java

Target person

Beginners who learned the basics of Java

Achievement goal

You can program based on the flowchart and functional details.

flowchart

detail of function

・ Product list initialization The following three products are fixed. Coke 100 yen Orange juice 120 yen Water 80 yen

·payment It is possible to deposit in units of 1 yen. Prompt to deposit until the minimum amount available for purchase is deposited. (In this case, 80 yen or more for water)

・ Product selection Display products within the deposit amount. Select by product name.

・ Sales Offer the selected product.

・ Billing Subtract the purchase price from the deposit amount. Return the change.

Sample code

package vm;

import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		//Product initialization
		Map<String, Integer> items = new HashMap<String, Integer>();
		items.put("Cola", 100);
		items.put("Orange juice", 120);
		items.put("water", 80);

		//Additional deposit for minimum purchase amount
		int deposit = 0;
		int minSaleAmount = -1;
		Scanner scanner = new Scanner(System.in);
		do {
			//Deposit processing
			System.out.println("Please put in the money.");
			deposit = deposit + scanner.nextInt();

			//Amount check (minimum purchase amount)
			int loopCount = 0;
			for (String itemKey: items.keySet()) {
				if(loopCount == 0 || minSaleAmount > items.get(itemKey)) {
					minSaleAmount = items.get(itemKey);
				}
				loopCount++;
			}
		} while(deposit < minSaleAmount);

		//Product selection
		System.out.println("Please select a product.");
		Map<String, Integer> availablePurchases = new HashMap<String, Integer>();
		for (String itemKey: items.keySet()) {
			if(deposit >= items.get(itemKey)) {
			System.out.println(itemKey + ":" + items.get(itemKey) + "Circle");
			availablePurchases.put(itemKey, items.get(itemKey));
			}
		}

		//Sale
		String itemName;
		while(true) {
			itemName = scanner.next();
			if (availablePurchases.containsKey(itemName)){
				break;
			}
			System.out.println("The product name is specified incorrectly. Please specify the product name again.");
		}
		scanner.close();
		System.out.println(itemName + "is!");

		//Billing function
		deposit = deposit - availablePurchases.get(itemName).intValue();
		System.out.println("Change is" + deposit + "It is a circle.");


	}

}

I have created a classified version. https://qiita.com/TakumiKondo/items/9f222f44c973bb2eaa06