﻿ C# exercises and solutions-C# array: statistical information

# C# exercises and solutions-C# array: statistical information

## C# array exercise: statistical information

Exercise : Write a C# program to answer about the statistical information such as arithmetic mean, median, mode, and standard deviation of an integer data set. The data points are input by the user from keyboard. This program will display the output similar to the one shown below:

If you are not sure about statistical information such as arithmetic mean, median, mode, and standard deviation, you will need to read this page:

Solution:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Csharp_exercises
{
class Program
{
static void Main(string[] args)
{
int n;
float mean,median,std;
Console.Write("Enter number of data points:");
if (n < 3)
{
Console.WriteLine("The number of data points should be greater than 2.");

}
else
{

//declare an array of n size to store integral data points
int[] dataset = new int[n];
//allow user inputs
int i = 0;
for (i = 0; i < n; i++)
{
Console.Write("[{0}]:", i);
}

//sort the data set
bubblesort(dataset, n);

//calculate the mean
int sum = 0;
int j = 0;
while (j < n)
{
sum = sum + dataset[j];
j++;
}

mean = (float)sum / n;

//calculate median
//If n is odd, median=dataset[n/2]
//If n is even, median=(dataset[n/2]+dataset[1+n/2])/2
//The index of array starts from 0, so you need to subtract 1 from the           //indices   used in calculating the median
if (n % 2 != 0) median = dataset[n / 2];
else median = (dataset[(n / 2) - 1] + dataset[n / 2]) / (float)2;

//calculate the mode
int[,] mode = new int[n, 2];
//initialize 2D array storing numbers of occurences, and values
for (i = 0; i < 2; i++)
for (j = 0; j < n; j++) mode[j, i] = 0;
mode[0, 0] = 1;

for (i = 0; i < n; i++)
for (j = 0; j < n - 1; j++)
if (dataset[i] == dataset[j + 1]) { ++mode[i, 0]; mode[i, 1] = dataset[i]; }

int max;
int k = 0;
max = mode[0, 0];
for (j = 0; j < n; j++)
if (max < mode[j, 0]) { max = mode[j, 0]; k = j; }

//calculate standard deviation, std
float temp = 0.0f;

for (j = 0; j < n; j++)
{
temp = temp + (float)Math.Pow(dataset[j] - mean, 2);
}

std = (float)Math.Sqrt(temp / (n - 1));

//Show results

Console.WriteLine("Statistical Information:");
Console.WriteLine("..................................................");
Console.WriteLine("Arithmetic mean:{0}", mean);
Console.WriteLine("Median:{0}", median);
if (mode[k, 1] != 0)
Console.WriteLine("Mode:{0}", mode[k, 1]);
else Console.WriteLine("Mode: no mode");
Console.WriteLine("Standard deviation:{0}", std);

}

}

///bubble sort

static void bubblesort(int[] dataset, int n)
{
int i, j;
for (i = 0; i < n; i++)
for (j = n - 1; j > i; j--)
if (dataset[j] < dataset[j - 1])
{
int temp = dataset[j];
dataset[j] = dataset[j - 1];
dataset[j - 1] = temp;
}

}
}
}