Where to put the code

I HAVE A PROGRAM HERE THAT COMPUTES FOR I/O UTILIZATION. THERE'S ONLY ONE PROBLEM, I CANT SEEM TO FIND THE RIGHT PLACE TO PUT THESE CODE:

CPU=(mss/(ms+mss+msss))*100;
JOptionPane.showMessageDialog(null, "CPU Utlization:"+CPU+"%");

AS YOU CAN SEE I PLACED THE CODE ON THE LAST PART BUT WHEN I COMPILE THERE'S AN ERROR SAYING
"variable ms might not have been initialized"

BUT I ALREADY DID INITIALIZE VARIABLE ms.

PLEASE LET ME KNOW WHERE TO PUT THE CODE SO THAT THE PROGRAM CAN FUNCTION RIGHT. THANKS

Code:

  
 import javax. swing.*; 
  
 public class CaseStudy{ 
  public static void main(String[]args){ 
  double ms, mss, msss, mssss, CPU; int input,charc,unit,unit1,unit2,unit3,unit4,card,output,lines,inst; 
  double sec=.010; 
   
  { 
    
   //INPUT PHASE 
       input=Integer.parseInt(JOptionPane.showInputDialog("Choose Input Device: \n (1)Keyboard \n (2)Cardreader")); 
          { 
           
         if (input==1){ 
             charc=Integer.parseInt(JOptionPane.showInputDialog("How Many Characters?")); 
 unit=Integer.parseInt(JOptionPane.showInputDialog("Number Of Characters:"+charc+"\n In What Unit Of Time?\n(1)Microsecond \n(2)Millisecond\n(3)Second \n(4)Minute")); 
                if (unit==1) 
                    mssss=(sec/charc); 
               else if (unit==2) 
                    mssss=(1/charc); 
              else if (unit==3) 
                    mssss=(1000/charc); 
               else 
                   mssss=(60000/charc); 
    
          JOptionPane.showMessageDialog(null, "Input Phase:"+mssss+"ms");}   
   
         else{ 
              card=Integer.parseInt(JOptionPane.showInputDialog("How Many Cards?")); 
 unit2=Integer.parseInt(JOptionPane.showInputDialog("Number Of Characters:"+card+"\n In What Unit Of Time?\n(1)Microsecond \n(2)Millisecond\n(3)Second \n(4)Minute")); 
                if (unit2==1) 
                    ms=(sec/card); 
               else if (unit2==2) 
                    ms=(1/card); 
              else if (unit2==3) 
                    ms=(1000/card); 
               else 
                   ms=(60000/card); 
      JOptionPane.showMessageDialog(null, "Input Phase:"+ms+"ms");}}    
   
      
   //OUTPUT PHASE 
       output=Integer.parseInt(JOptionPane.showInputDialog("Choose Printer: (1)Laser (2)DotMatrix")); 
         {if (input==1){ 
          lines=Integer.parseInt(JOptionPane.showInputDialog("How Many Lines?")); 
 unit3=Integer.parseInt(JOptionPane.showInputDialog("Number Of Lines:"+lines+"\n In What Unit Of Time?\n(1)Microsecond \n(2)Millisecond\n(3)Second \n(4)Minute")); 
                if (unit3==1) 
                    msss=(sec/lines); 
               else if (unit3==2) 
                    msss=(1/lines); 
              else if (unit3==3) 
                    msss=(1000/lines); 
               else 
               msss=(60000/lines); 
   JOptionPane.showMessageDialog(null, "Output Phase:"+msss+"ms");} 
         else{ 
          lines=Integer.parseInt(JOptionPane.showInputDialog("How Many Lines?")); 
 unit3=Integer.parseInt(JOptionPane.showInputDialog("Number Of Lines:"+lines+"\n In What Unit Of Time?\n(1)Microsecond \n(2)Millisecond\n(3)Second \n(4)Minute")); 
                if (unit3==1) 
                    msss=(sec/lines); 
               else if (unit3==2) 
                    msss=(1/lines); 
              else if (unit3==3) 
                    msss=(1000/lines); 
               else 
                   msss=(60000/lines); 
   JOptionPane.showMessageDialog(null, "Output Phase:"+msss+"ms");}} 
       
   //PROCESS PHASE 
    inst=Integer.parseInt(JOptionPane.showInputDialog("How Many Instructions?")); 
unit4=Integer.parseInt(JOptionPane.showInputDialog("Instructions:"+inst+"\n In What Unit Of Time?\n(1)Microsecond \n(2)Millisecond\n(3)Second \n(4)Minute")); 
                {if (unit4==1) 
                    mss=(inst/1000); 
                else if (unit4==2) 
                    mss=(inst/1); 
                else if (unit4==3) 
                    mss=(inst/sec); 
                else 
                    mss=(inst/60000); 
    JOptionPane.showMessageDialog(null, "Process Phase:"+mss+"ms"); 
 //CPU Utilization 
 CPU=(mss/(ms+mss+msss))*100; 
 JOptionPane.showMessageDialog(null, "CPU Utlization:"+CPU+"%");} 
   
  
 }}}

 

Code:

  public static void main(String[]args){ 
  double ms=[COLOR=Red]0[/COLOR], mss, msss, mssss, CPU; int input,charc,unit,unit1,unit2,unit3,unit4,card,output,lines,inst; 
  double sec=.010;

when you give a value to a variable inside an if
it is not certain that it will actually get a value!
that is why you get this error.