Reporting quarterly changes for each department

This code works 100%, but I am trying to see if I can use a for-statement to make my second method less-cumbersome and more efficient instead of making so many variables.

I have to show the differences between each quarter for every department.

My array has 6 Departments and 4 Quarters.

import java.util.*;
public void setQuarter()
{
    final int DEPARTMENT = 6;
    final int QUARTER = 4;
    private static double [][] sales = new double [DEPARTMENT][QUARTER];
    Scanner  keyboard = new Scanner(System.in);
    double total = 0;

    for (int row = 0; row < DEPARTMENT ; row++)
    {
        for (int col = 0; col < QUARTER; col++)
        {
            // This will input value into my array
            System.out.print(" \n What Were The Total Sales For Department : " + (row + 1 ) + " Quarter : " + (col + 1 ) + " = ");
            sales[row][col] = keyboard.nextDouble();
        }
    }
}

This is the only thing that I could come up with, since I am new to Java and 2-D arrays. I want to know if there is an easier way of getting the quarterly differences for each department. I was told I could use a nested for-statement to subtract the elements in the 2-D array. However, I have tried but I can't seem to get one done. I am pretty sure the use of a nested for-statement would clean my code up quickly. Can anyone help me out with this?

```
public void departmentdiff()
{
double dept1Qrt1 = sales [0] [0];
double dept2Qrt1 = sales [1] [0];
double dept3Qrt1 = sales [2] [0];
double dept4Qrt1 = sales [3] [0];
double dept5Qrt1 = sales [4] [0];
double dept6Qrt1 = sales [5] [0];
double dept1Qrt2 = sales [0] [1];
double dept2Qrt2 = sales [1] [1];
double dept3Qrt2 = sales [2] [1];
double dept4Qrt2 = sales [3] [1];
double dept5Qrt2 = sales [4] [1];
double dept6Qrt2 = sales [5] [1];
double dept1Qrt3 = sales [0] [2];
double dept2Qrt3 = sales [1

Refactoring should get you there

total1 = dept1Qrt1 - dept1Qrt2;
    total2 = dept1Qrt2 - dept1Qrt3;
    total3 = dept1Qrt3 - dept1Qrt4;
    System.out.println( " \n The Quarterly Differences For Department-1 is :");
    System.out.println( " ********************************************** ");
    System.out.println( " \n From Quarter : 1 to Quarter : 2 The Difference Is ( " + total1 + " ) ");
    System.out.println( " \n From Quarter : 2 to Quarter : 3 The Difference Is ( " + total2 + " ) ");
    System.out.println( " \n From Quarter : 3 to Quarter : 4 The Difference Is ( " + total3 + " ) ");

We're going to make it look worse for a moment...

total1 = sales [0] [0]- sales [0] [1];
    total2 = sales [0] [1]- sales [0] [2];
    total3 = sales [0] [2]- sales [0] [3];
    System.out.println( " \n The Quarterly Differences For Department-1 is :");
    System.out.println( " ********************************************** ");
    System.out.println( " \n From Quarter : 1 to Quarter : 2 The Difference Is ( " + total1 + " ) ");
    System.out.println( " \n From Quarter : 2 to Quarter : 3 The Difference Is ( " + total2 + " ) ");
    System.out.println( " \n From Quarter : 3 to Quarter : 4 The Difference Is ( " + total3 + " ) ");

Re arrange, so things line up better

System.out.println( " \n The Quarterly Differences For Department-1 is :");
    System.out.println( " ********************************************** ");
    total1 = sales [0] [0]- sales [0] [1];
    System.out.println( " \n From Quarter : 1 to Quarter : 2 The Difference Is ( " + total1 + " ) ");
    total2 = sales [0] [1]- sales [0] [2];
    System.out.println( " \n From Quarter : 2 to Quarter : 3 The Difference Is ( " + total2 + " ) ");
    total3 = sales [0] [2]- sales [0] [3];
    System.out.println( " \n From Quarter : 3 to Quarter : 4 The Difference Is ( " + total3 + " ) ");

Inject a variable to represent the quarter

System.out.println( " \n The Quarterly Differences For Department-1 is :");
    System.out.println( " ********************************************** ");
    int quarter = 0;
    total1 = sales [0] [quarter]- sales [0] [quarter+1];
    System.out.println( " \n From Quarter : 1 to Quarter : 2 The Difference Is ( " + total1 + " ) ");
    quarter = 1;
    total2 = sales [0] [quarter]- sales [0] [quarter+1];
    System.out.println( " \n From Quarter : 2 to Quarter : 3 The Difference Is ( " + total2 + " ) ");
    quarter = 2;
    total3 = sales [0] [quarter]- sales [0] [quarter+1];
    System.out.println( " \n From Quarter : 3 to Quarter : 4 The Difference Is ( " + total3 + " ) ");

Now it should be obvious where the for loop falls out; note the introduction of "quarterNames", which is a lookup table (aka array) to make sure the spellings are correct in the strings; you need to do something to ensure that you don't confuse 1-based humans by printing 0-based identifiers.

System.out.println( " \n The Quarterly Differences For Department-1 is :");
    System.out.println( " ********************************************** ");
    for (int quarter = 0; quarter < 3; ++quarter {
        double total = sales [0] [quarter]- sales [0] [quarter+1];
        System.out.println( " \n From Quarter : " + quarterNames[quarter] + " to Quarter : " + quarterNames[quarter+1] + " The Difference Is ( " + total + " ) ");
    }

For more readability, use better variable names

System.out.println( " \n The Quarterly Differences For Department-1 is :");
    System.out.println( " ********************************************** ");
    for (int thisQuarter = 0; thisQuarter < 3; ++thisQuarter {
        int nextQuarter = 1 + thisQuarter;

        double total = sales [0] [thisQuarter]- sales [0] [nextQuarter];
        System.out.println( " \n From Quarter : " + quarterNames[thisQuarter] + " to Quarter : " + quarterNames[nextQuarter] + " The Difference Is ( " + total + " ) ");
    }

Eliminate some magic numbers

int thisDepartment = 0;
    System.out.println( " \n The Quarterly Differences For Department-" + departmentId[thisDepartment] + " is :");
    System.out.println( " ********************************************** ");
    for (int thisQuarter = 0; thisQuarter < QUARTER; ++thisQuarter {
        int nextQuarter = 1 + thisQuarter;

        double total = sales [thisDepartment] [thisQuarter]- sales [thisDepartment] [nextQuarter];
        System.out.println( " \n From Quarter : " + quarterNames[thisQuarter] + " to Quarter : " + quarterNames[nextQuarter] + " The Difference Is ( " + total + " ) ");
    }

At this point, it should be clear how to create a for loop that generates the report for each department.

BUT: more advanced programmers wouldn't do it this way. Part of the reason that this is such a mess, is that you are storing each piece of data independently, and then trying to reconstruct the data relationships.

In this example, there are three (simple) abstractions. There's the concept of a "quarter", th

StackExchange Code Review Q#35276, answer score: 8