Practice Exercises Java - Learn to program performing exercises with Java

Practice Exercises Java

Learn to program performing exercises with Java

12 Lessons Java with the Solutions - 228 Exercises Java with the solutions
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Unlimited sum - Practice Exercises Java

Lesson 11:

Dynamic memory management

Exercise 11.7:

Unlimited sum


Create a program to allow the user to enter an unlimited amount of numbers. Also, they can enter the following commands:

"sum", to display the sum of all the numbers entered so far.
"view", to display all the numbers entered.
"end", to quit the program.

This is an execution sample:
Number or command? 5
Number or command? 3
Number or command? view

Entered numbers:

Number or command? 6
Number or command? sum
Sum = 14
Number or command? -7
Number or command? end

Source Code:

package Comands;
import java.util.*;
public class Main
	static void main(String[] args)
		boolean exit = false;

		String answer;

		ArrayList mylist = new ArrayList();
		int total = 0;
			System.out.print("Number or command? ");
			answer = new Scanner(;

			if (answer.toLowerCase().equals("view"))
				System.out.println("Entered numbers: ");
				for (int number : mylist)
			else if (answer.toLowerCase().equals("sum"))
				System.out.printf("Sum: %1$s" + "\r\n", total);
			else if (answer.toLowerCase().equals("end"))
				exit = true;
					int number = Integer.parseInt(answer);
					total += number;
				catch (java.lang.Exception e)
					System.out.println("Command is not recognized by the system");
		} while (!exit);

Exercisey 11.7

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