Census Data Display from Text File

This program is for a class project and requires me to read data from a text file then display a list of totals. Here are the instructions/requirements:


The fields in each record will be separated by a comma.


Format: Age, Gender, Marital Status, District#


For example: 18, M, S, 2


The city has 22 districts. The census department wants to see a
listing of how many residents are in each district, and a count of
residents in each of the following age groups (for all the districts
combined): under 18, 18 through 30, 31 through 45, 46 through 64, and
65 or older.

The only way I can get this to work was using a bunch of if statements (which is bad I've been told). Is there a way for me to just read through the data and put the correct age/district number in an array, then display the totals for the each Age Group (groups 1-5) and District (1-22)?

So say each time the program reads age 18 and district 2 for example, it will add 1 to Age Group 1 and 1 to District 2 that element and so on? Then at the end just display the results? I just barely learned about array and I don't know how I can do this.

```
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;

namespace Project2
{
class Program
{
static void Main(string[] args)
{
int[] ageData = new int[900];
int[] districtDataA = new int[900];
int[] ageGroup = new int[5];
int[] districtCount = new int[22];
int i = 0;
foreach (string line in File.ReadAllLines("test.txt"))
{
string[] fields = line.Split(',');

ageData[i] = int.Parse(fields[0]);
districtDataA[i] = int.Parse(fields[3]);

if (ageData[i] > 0 && ageData[i] 18 && ageData[i] 30 && ageData[i] 45 && ageData[i] = 65)
{
ageGroup[4] = ageGroup[4] + 1;
}

//District Count info

Try to visualize how your items are related. Think how your code runs, step by step, like in slow-mo. You will realize you can sum up long and tedious code into simplest, more abstract, styles.

Let me start from the last portion of your code:

Console.WriteLine("District 1 = {0}", districtCount[0]);
    Console.WriteLine("District 2 = {0}", districtCount[1]);
    Console.WriteLine("District 3 = {0}", districtCount[2]);
    //etc etc

If you find yourself writing repetitive lines as you have here, there is almost always a better way to code that. Here, a simple loop makes sense:

for (int i = 1; i <= 22; i++)
    {
        Console.WriteLine("District {0} = {1}", i, districtCount[i-1]);
    }

That makes it short and readable, less convoluted. We merely extracted the 1,2,3... and the 0,1,2... into i and i-1 respectively.

Now using the same "trick" you can replace all your ifs (which should have been if else's in the first place) with just a single line:

districtCount[districtDataA[i] - 1]++;

BONUS: When you want to type variable = variable + 1 it's shorter and more readable if you type variable++ instead. Same with variable--. For different amounts, you can do variable += amount (also -=, *=, /= and more operators depending on the language)

StackExchange Code Review Q#46507, answer score: 6