How to Get Main output into Common() method in Java?

Java programming Reverse Integers by calling a method?

• Hello, I am new to java programming and I apologize if the way I am asking for help is a little hard to understand because I don't fully comprehend the terminology of java. Essentially, I am asked in a homework assignment to use a while loop to present the reverse integers of 12345 in a pop up box window format. Using a return statement and by calling a method at the end of the main method. I suppose that's a clear as I can make it as far as pseudo code goes, here is what I have right now-- maybe this will make it easier for you to understand what I'm trying to do. The code doesn't compile and I'm clearly missing something. //Instructor: Jigang Liu //Student: Ryan Carlson //assignemtn: 5 part 2 //Compiler: JDK 1.7 with Text Pad //Due Date: 02/27/12 //Description: Based on the exercise in the book 5.4 on page 189, us the template we discussed in class in order to call for your method to reverse the input import javax.swing.JOptionPane; public class MyReverse { public static void main(String[] args) { //define variables String num1Str, message; int num1, reverseNum; //Enter an integer num1Str = JOptionPane.showInputDialog("Enter a positive integer:"); num1 = Integer.parseInt(num1Str); //Call a method "reverseIntegers with an argument "num1" reverseNum = reverseIntegers(num1); //Assemble the output message = "Reverse integer for " + num1 + " is " + reverseNum; //output the result JOptionPane.showMessageDialog(null, message); }//end of the main public static int reverseIntegers(int myInput) { int temp1 = myInput % 10; while(myInput > 0) { temp1 = myInput % 10; //get the last digit myInput = myInput / 10;//remove the last digit return temp1; } Let me know if you can help, thanks.

• Answer:

  Okay your biggest mistake and also the reason why it won't compile is the return statement inside the loop, because it could be possible that a loop doesn't run and in this case would be no return statement! Another problem with the return statement inside a loop, is that the return statement exits the loop immediately -> therefore ther would only be one run inside the loop (which makes no sense). Just write the return statement outside the loop. Your second mistake is that you reset the temp1 mehod everytime: temp1 = myInput % 10; //you'll only return one digit!! To add digits you can write: temp1 = temp1 + myInput % 10; or temp1 += myInput % 10; However that's still not the whole solution. Let's solve it by using an example, our numer is 28. We want to get 82, but if we add 8 & 2 like in the code below - it won't work. temp1 = temp1 + myInput % 10; What we have to do is always multiplying our temp1 by 10 before adding the next number to move our current numbers one position further. 1) temp1=8 2) temp1=temp1*10 -> temp1=80 3) temp1=temp1+2 -> temp1=82 So your final method would look like this: public static int reverseIntegers(int myInput) { int temp1 = myInput % 10; while(myInput > 0) { temp1 = temp1 * 10; //Move our numbers one position to the left leaving a zero on the right temp1 = temp1 + myInput % 10; //Fill in the real number instead of the zero myInput = myInput / 10;//Remove the last digit and repeat } return temp1; } Feel free to ask if you don't understand. Cheers Raphael