How to add a new method called numberOfDigits() in java?

Question

I have a program called public class ZeroCounter {. I want to add a new method to it called numberOfDigits() and add a line to test it in the main() method. How should I go abo

Answer 1

Try this method to count digits of an integer number:-

 public int numberOfZeros(int number){
    return ((int) Math.log10(number) + 1);
}

Or you can try this code

      //Declare input as scanner
        Scanner input = new Scanner(System.in);

        //Take input
         System.out.println("Enter Number :");
         no = input.nextInt();
         System.out.println("Enter digit :");
         digit = input.nextInt();

        //add while loop
        while(no>0)
        {
            m=no%10;
            if(m==digit)
                oc++;
            no=no/10;
        }

        System.out.println("Digit occurred "+oc+" times");

Answer 2

public class ZeroCounter   {
  public static void main(String[] args) {
         System.out.println("Enter a nonnegative number:");
         Scanner keyboard = new Scanner(System.in);
         int number = keyboard.nextInt( ) ;

         System.out.println(number + " contains " + numberOfZeros(number) + " zeros.");
  } // End of main

  private static int numberOfZeros(int number) {
         int result = ///// calculation
         return result;
  }
}

You might want to read up a bit more on Java and how classes, methods and functions work first before going any further however.

Answer 3

It should be:

public class ZeroCounter {

    public static int numberOfDigits(int number) {
        //- Implementation goes here.
    }

    public static void main(String[] args) {
        int number;
        //- Initialize number variable.
        System.out.println("numberOfDigits(" + number + ")=" + numberOfDigits(number));
    }
}

Answer 4

Try this.... :)

public class ZeroCounter {

    public static int numberOfDigits(int number) 
    {
        //return Integer.toString(number).length();
        return String.valueOf(number).length();
    }

    public static void main(String[] args)
    {
        int number;
        Scanner Keyboard=new Scanner(System.in);
        System.out.print("Enter the number: ");
        number=Keyboard.nextInt();
        System.out.println("numberOfDigits(" + number + ")=" + numberOfDigits(number));
    }
}

Updated Code..

import java.util.*;
public class ZeroCounter 
{

public static int numberOfDigits(int number,char d) 
{           
    //to get a char array of digits of number
    char[] n=Integer.toString(number).toCharArray();
    int r=0;
    for(char x:n)
    {
        if(x==d)
            r++;
    }
    return r;
}

public static void main(String[] args)
{
    int number;
    char digit;
    boolean flag=false;
    Scanner Keyboard=new Scanner(System.in);
    try{
    System.out.print("Enter the non-negative number: ");
    number=Keyboard.nextInt();

    //to check number is positive or not
    if(number<=-1)
    throw new Exception();
    System.out.println(number + " contains " + numberOfDigits(number,'0') + " zeros.");
    System.out.print("Enter the digit: ");

    //to take only one letter as input
    digit=Keyboard.next(".").charAt(0);

    //to check input is digit or not
    if(!Character.isDigit(digit))
    throw new Exception();
    System.out.println("Number of digits(" + digit + ")=" + numberOfDigits(number,digit));
    }
       //to catch all exceptions
    catch(Exception e)
    {  
        System.out.println("\n You have entered invalid input..");
    }
}
}