Export Data to Excel in Java

Question

Im having java code to make calculation for mathematical formula , and i wanna to export it to excel sheet , but when i do that the value the came from the calculation it become +1 and i don't know how to fix this , so please can you help me guys , below you will see my code line and screen shot from excl sheet where data are export

      public class Test {
public static void main(String[] args) {
    double i = .5;
    double   x1 =1,x2=.001,x3=0.0005,c1=17.3387,c2=46.6885,c3=11.4775,c4=8.5316,c5=0.6561,c6=0.0907;
     double deltakfuel,deltakamod,deltakcr = 0,deltak,xprim = 0;

    System.out.println ("hello");

    for (int t=0;  t<2; t=t+1){



         if ((t>0 & t<10)){
         deltakcr = (i*1E-5/10)/t;

     }
     else if (t>60 & t<70){
         deltakcr = (1E-5)*(i-8*(t-60));

         } else
         if (t<70){
             deltakcr =-30E-5;
         }
             deltakfuel =  -3.1E-5*x2+.0031E-5;
             System.out.println("The value of DeltaKfuel = " +deltakfuel++);

             deltakamod = -.6E-5*x3+.0003E-5;
             System.out.println("The value of DeltaKmoderater = " +deltakamod++);

     System.out.println("The value of DeltaKcontrol rod = " +deltakcr++);

     deltak=deltakfuel+deltakamod+deltakcr;
     System.out.println("The Total value of DeltaK = " +deltakcr++);

     xprim = ((deltak/.001-6.502)*x1+.0124*c1+.0305*c2+.111*c3+.301*c4+1.14*c5+3.01*c6);
     System.out.println("The total value of dn/dt = " +xprim++);
     }
     double dc1 = .21500*x1-.0214*c1;
     double dc2= 1.424000*x1-0.0305*c2;
     double dc3= 1.274000*x1-0.1110*c3;
     double dc4= 2.568000*x1-0.3010*c4;
     double dc5= 0.748000*x1-1.1400*c5;
     double dc6= 0.273000*x1-3.0100*c6;
     double dc7= 0.000200*x1-0.2000*x2;
     double dc8 =0.000005*x1-0.0100*x3;
     System.out.println("The value of dc1/dt = "+dc1++);
     System.out.println("The value of dc2/dt = "+dc2++);
     System.out.println("The value of dc3/dt = "+dc3++);
     System.out.println("The value of dc4/dt = "+dc4++);
     System.out.println("The value of dc5/dt = "+dc5++);
     System.out.println("The value of dc6/dt = "+dc6++);
     System.out.println("The value of dc7/dt = "+dc7++);
     System.out.println("The value of dc8/dt = "+dc8++);



        XSSFWorkbook workbook = new XSSFWorkbook(); 

        //Create a blank sheet
        XSSFSheet sheet = workbook.createSheet("Data");

        //This data needs to be written (Object[])
        Map<String, Object[]> data = new TreeMap<String, Object[]>();
        data.put("1", new Object[] { "Value", "Value"});
        data.put("2", new Object[] { ""+dc7,  ""+dc7});



        //Iterate over data and write to sheet
        Set<String> keyset = data.keySet();
        int rownum = 0;
        for (String key : keyset)
        {
            Row row = sheet.createRow(rownum++);
            Object [] objArr = data.get(key);
            int cellnum = 0;
            for (Object obj : objArr)
            {
               Cell cell = row.createCell(cellnum++);
               if(obj instanceof String)
                    cell.setCellValue((String)obj);
                else if(obj instanceof Integer)
                    cell.setCellValue((Integer)obj);
            }
        }
        try 
        {
            //Write the workbook in file system
            FileOutputStream out = new FileOutputStream(new File("howtodoinjava_demo.xlsx"));
            workbook.write(out);
            out.close();

            System.out.println("howtodoinjava_demo.xlsx written successfully on disk.");

        } 
        catch (Exception e) 
        {
            e.printStackTrace();
        }
}
}

and this the output from java

           hello
          The value of DeltaKfuel = 0.0
          The value of DeltaKmoderater = 0.0
          The value of DeltaKcontrol rod = -3.0E-4
          The Total value of DeltaK = 0.9997
          The total value of dn/dt = 2999.6999742299995
          The value of DeltaKfuel = 0.0
          The value of DeltaKmoderater = 0.0
          The value of DeltaKcontrol rod = 5.000000000000001E-7
          The Total value of DeltaK = 1.0000005
          The total value of dn/dt = 3000.00047423
          The value of dc1/dt = -0.15604817999999995
          The value of dc2/dt = 7.500000001048335E-7
          The value of dc3/dt = -2.4999999999053557E-6
          The value of dc4/dt = -1.1599999999667432E-5
          The value of dc5/dt = 4.599999999999049E-5
          The value of dc6/dt = -6.999999999979245E-6
          The value of dc7/dt = 0.0
          The value of dc8/dt = 0.0
          howtodoinjava_demo.xlsx written successfully on disk.

Excel output from java class showing that dc8/dt value became +1 from 0.0 to 1.0

Answer 1

there is dc7++ and dc8++ after your calculation. This variable++ operation will increment the variable by one but return the original value.