Need help with calculator project for an assignment...

Question

Hi all, I please need help with my calculator project that I have to do for an assignment.
Here is the project's specifications that I need to do"
"""Create a console calculator applicaion that:
* Takes one command line argument: your name and surname. When the
program starts, display the date and time with a welcome message for the
user.
* Display all the available options to the user. Your calculator must include
the arithmetic operations as well as at least five scientific operations of the
Math class.
-Your program must also have the ability to round a number and
truncate it.
-When you multiply by 2, you should not use the '*' operator to perform the
operation.
-Your program must also be able to reverse the sign of a number.
* Include sufficient error checking in your program to ensure that the user
only enters valid input. Make use of the String; Character, and other
wrapper classes to help you.
* Your program must be able to do conversions between decimal, octal and
hex numbers.
* Make use of a menu. You should give the user the option to end the
program when entering a certain option.
* When the program exits, display a message for the user, stating the
current time, and calculate and display how long the user used your
program.
* Make use of helper classes where possible.
* Use the SDK to run your program."""
When the program starts, it asks the user for his/her name and surname. I got the program to ask the user again and again for his/her name and surname
when he/she doesn't insert anything or just press 'enter', but if the user enters a number for the name and surname part, the program continues.
Now my question is this: How can I restrict the user to only enter 'letters' (and spaces of course) but allow NO numbers for his/her surname??
Here is the programs code that I've written so far:
{code}
import java.io.*;
import java.util.*;
import java.text.*;
public class Project {
     private static String nameSurname = "";     
     private static String num1 = null;
     private static String num2 = null;
     private static String choice1 = null;
     private static double answer = 0;
     private static String more;
     public double Add() {
          answer = (Double.parseDouble(num1) + Double.parseDouble(num2));
          return answer;
     public double Subtract() {
          answer = (Double.parseDouble(num1) - Double.parseDouble(num2));
          return answer;
     public double Multiply() {
          answer = (Double.parseDouble(num1) * Double.parseDouble(num2));
          return answer;
     public double Divide() {
          answer = (Double.parseDouble(num1) / Double.parseDouble(num2));
          return answer;
     public double Modulus() {
          answer = (Double.parseDouble(num1) % Double.parseDouble(num2));
          return answer;
     public double maximumValue() {
          answer = (Math.max(Double.parseDouble(num1), Double.parseDouble(num2)));
          return answer;
     public double minimumValue() {
          answer = (Math.min(Double.parseDouble(num1), Double.parseDouble(num2)));
          return answer;
     public double absoluteNumber1() {
          answer = (Math.abs(Double.parseDouble(num1)));
          return answer;
     public double absoluteNumber2() {
          answer = (Math.abs(Double.parseDouble(num2)));
          return answer;
     public double Squareroot1() {
          answer = (Math.sqrt(Double.parseDouble(num1)));
          return answer;
     public double Squareroot2() {
          answer = (Math.sqrt(Double.parseDouble(num2)));
          return answer;
     public static String octalEquivalent1() {
          int iNum1 = Integer.parseInt(num1);
String octal1 = Integer.toOctalString(iNum1);
return octal1;
     public static String octalEquivalent2() {
          int iNum2 = Integer.parseInt(num2);
          String octal2 = Integer.toOctalString(iNum2);
          return octal2;
     public static String hexadecimalEquivalent1() {
          int iNum1 = Integer.parseInt(num1);
          String hex1 = Integer.toHexString(iNum1);
          return hex1;
     public static String hexadecimalEquivalent2() {
          int iNum2 = Integer.parseInt(num2);
          String hex2 = Integer.toHexString(iNum2);
          return hex2;
     public double Round1() {
          answer = Math.round(Double.parseDouble(num1));
          return answer;
     public double Round2() {
          answer = Math.round(Double.parseDouble(num2));
          return answer;
          SimpleDateFormat format1 = new SimpleDateFormat("EEEE, dd MMMM yyyy");
     Date now = new Date();
     SimpleDateFormat format2 = new SimpleDateFormat("hh:mm a");
     static Date timeIn = new Date();
     public static long programRuntime() {
          Date timeInD = timeIn;
          long timeOutD = System.currentTimeMillis();
          long msec = timeOutD - timeInD.getTime();
          float timeHours = msec / 1000;
               return (long) timeHours;
     DecimalFormat decimals = new DecimalFormat("#0.00");
     public String insertNameAndSurname() throws IOException{
          boolean inputCorrect = false;
               while (inputCorrect == false) {
                    while (nameSurname == null || nameSurname.length() == 0) {
                         for (int i = 0; i < nameSurname.length(); i++) {
                         if ((nameSurname.charAt(i) > 'a') && (nameSurname.charAt(i) < 'Z')){
                                   inputCorrect = true;
                    else{
                    inputCorrect = false;
                    break;
                    try {
                         BufferedReader inStream = new BufferedReader (new InputStreamReader(System.in));
                         System.out.print("Please enter your name and surname: ");
                         nameSurname = inStream.readLine();
                         inputCorrect = true;
                    }catch (IOException ex) {
                         System.out.println("You did not enter your name and surname, " + nameSurname + " is not a name, please enter your name and surname :");
                         inputCorrect = false;
                    System.out.println("\nA warm welcome " + nameSurname + " ,todays date is: " + format1.format(now));
                    System.out.println("and the time is now exactly " + format2.format(timeIn) + ".");
                    return nameSurname;
          public String inputNumber1() throws IOException {
          boolean inputCorrect = false;
               while (inputCorrect == false) {
                    try {
                         BufferedReader br = new BufferedReader (new InputStreamReader(System.in));
                         System.out.print("\nPlease enter a number you want to do a calculation with and hit <ENTER>: ");
                         num1 = br.readLine();
                         double number1 = Double.parseDouble(num1);
                         System.out.println("\nThe number you have entered is: " + number1);
                         inputCorrect = true;
                    } catch (NumberFormatException nfe) {
                         System.out.println("\nYou did not enter a valid number: " + "\""+ num1 + "\" is not a number!!");
                         inputCorrect = false;
                    return num1;
     public String calculatorChoice() throws IOException {
          System.out.println("Please select an option of what you would like to do with this number from the menu below and hit <ENTER>: ");
          System.out.println("\n*********************************************");
          System.out.println("---------------------------------------------");
          System.out.println("Please select an option from the list below: ");
          System.out.println("---------------------------------------------");
          System.out.println("1 - Add");
          System.out.println("2 - Subtract");
          System.out.println("3 - Multiply");
          System.out.println("4 - Divide (remainder included)");
          System.out.println("5 - Maximum and minimum value of two numbers");
          System.out.println("6 - Squareroot");
          System.out.println("7 - Absolute value of numbers");
          System.out.println("8 - Octal and Hexadecimal equivalent of numbers");
          System.out.println("9 - Round numbers");
          System.out.println("0 - Exit program");
          System.out.println("**********************************************");
          boolean inputCorrect = false;
               while (inputCorrect == false) {
                    try {
                         BufferedReader inStream = new BufferedReader (new InputStreamReader(System.in));
                         System.out.print("Please enter your option and hit <ENTER>: ");
                         choice1 = inStream.readLine();
                         int c1 = Integer.parseInt(choice1);
                         System.out.println("\nYou have entered choice number: " + c1);
                         inputCorrect = true;
                    } catch (NumberFormatException nfe) {
                         System.out.println("You did not enter a valid choice number: " + "\""+ choice1 + "\" is not in the list!!");
                         inputCorrect = false;
                    return choice1;
     public String inputNumber2() throws IOException {
          boolean inputCorrect = false;
               while (inputCorrect == false) {
                    try {
                         BufferedReader br2 = new BufferedReader (new InputStreamReader(System.in));
                         System.out.print("\nPlease enter another number you want to do the calculation with and hit <ENTER>: ");
                         num2 = br2.readLine();
                         double n2 = Double.parseDouble(num2);
                         System.out.println("\nThe second number you have entered is: " + n2);
                         System.out.println("\nYour numbers are: " + num1 + " and " + num2);
                         inputCorrect = true;
                    } catch (NumberFormatException nfe) {
                         System.out.println("You did not enter a valid number: " + "\""+ num2 + "\" is not a number!!");
                         inputCorrect = false;
                    return num2;
     public int Calculator() {
          int choice2 = (int) Double.parseDouble(choice1);
          switch (choice2) {
                    case 1 :
                         Add();
                         System.out.print("The answer of " + num1 + " + " + num2 + " is: " + decimals.format(answer));
                         break;
                    case 2 :
                         Subtract();
                         System.out.print("The answer of " + num1 + " - " + num2 + " is: " + decimals.format(answer));
                         break;
                    case 3 :
                         Multiply();
                         System.out.print("The answer of " + num1 + " * " + num2 + " is: " + decimals.format(answer));
                         break;
                    case 4 :
                         Divide();
                         System.out.print("The answer of " + num1 + " / " + num2 + " is: " + decimals.format(answer));
                         Modulus();
                         System.out.print(" and the remainder is " + decimals.format(answer));
                         break;
                    case 5 :
                         maximumValue();
                         System.out.println("The maximum number between the numbers " + num1 + " and " + num2 + " is: " + decimals.format(answer));
                         minimumValue();
                         System.out.println("The minimum number between the numbers " + num1 + " and " + num2 + " is: " + decimals.format(answer));
                         break;
                    case 6 :
                         Squareroot1();
                         System.out.println("The squareroot of value " + num1 + " is: " + decimals.format(answer));
                         Squareroot2();
                         System.out.println("The squareroot of value " + num2 + " is: " + decimals.format(answer));
                         break;
                    case 7 :
                         absoluteNumber1();
                         System.out.println("The absolute number of " + num1 + " is: " + decimals.format(answer));
                         absoluteNumber2();
                         System.out.println("The absolute number of " + num2 + " is: " + decimals.format(answer));
                         break;
                    case 8 :
                         octalEquivalent1();
                         System.out.println("The octal equivalent of " + num1 + " is: " + octalEquivalent1());
                         octalEquivalent2();
                         System.out.println("The octal equivalent of " + num2 + " is: " + octalEquivalent2());
                         hexadecimalEquivalent1();
                         System.out.println("\nThe hexadecimal equivalent of " + num1 + " is: " + hexadecimalEquivalent1());
                         hexadecimalEquivalent2();
                         System.out.println("The hexadecimal equivalent of " + num2 + " is: " + hexadecimalEquivalent2());
                         break;
                    case 9 :
                         Round1();
                         System.out.println("The rounded number of " + num1 + " is: " + decimals.format(answer));
                         Round2();
                         System.out.println("The rounded number of " + num2 + " is: " + decimals.format(answer));
                         break;
                    case 0 :
                         if (choice2 == 0) {
                              System.exit(1);
                         break;
               return choice2;
          public String anotherCalculation() throws IOException {
               boolean inputCorrect = false;
               while (inputCorrect == false) {
                         try {                              
                              BufferedReader br3 = new BufferedReader (new InputStreamReader(System.in));
                              System.out.print("\nWould you like to do another calculation? Y/N ");
                              more = br3.readLine();
                              String s1 = "y";
                              String s2 = "Y";
                              if (more.equals(s1) || more.equals(s2)) {
                                   inputCorrect = true;
                                   while (inputCorrect = true){
                                        inputNumber1();
                                        System.out.println("");
                                        calculatorChoice();
                                        System.out.println("");
                                        inputNumber2();
                                        System.out.println("");
                                        Calculator();
                                        System.out.println("");
                                        anotherCalculation();
                                        System.out.println("");
                                        inputCorrect = true;
                              } else {
                                   System.out.println("\n" + nameSurname + " thank you for using this program, you have used this program for: " + decimals.format(programRuntime()) + " seconds");
                                   System.out.println("the program will now exit, Goodbye.");
                                   System.exit(0);
                         } catch (IOException ex){
                              System.out.println("You did not enter a valid answer: " + "\""+ more + "\" is not in the list!!");
                              inputCorrect = false;
          return more;
     public static void main(String[] args) throws IOException {
          Project p1 = new Project();
          p1.insertNameAndSurname();
          System.out.println("");
          p1.inputNumber1();
          System.out.println("");
          p1.calculatorChoice();
          System.out.println("");
          p1.inputNumber2();
          System.out.println("");
          p1.Calculator();
               System.out.println("");
               p1.anotherCalculation();
               System.out.println("");
{code}
*Can you please run my code for yourself and have a look at how this program is constructed*
*and give me ANY feedback on how I can better this code(program) or if I've done anything wrong from your point of view.*
Your help will be much appreciated.
Thanks in advance

Answer 1

Smirre wrote:
Now my question is this: How can I restrict the user to only enter 'letters' (and spaces of course) but allow NO numbers for his/her surname??You cannot restrict the user. It is a sad fact in programming that the worst bug always sits in front of the Computer.
What you could do is checking the input string for numbers. If it contains numbers, just reprompt for the Name.
AND you might want to ask yourself why the heck a calculator needs to know the users Name.