Some Little Questions

1- Write a program that increases each element of a 2D matrix by the average of all elements of the matrix.

2- Write a program that asks for the dimension N, 1 < N = 10 and calculates the entries a_ij of a square matrix A as a_ij = i + j. The program then asks for an integer number M, 1 = M = 20 and calculates the value S as follows,

Print S out to the screen. Also, print A out to the screen as a table of numbers. Provide a check of the condition 1 < N = 10 in your program. Validate the program for N of your choice.

Hint: For the questions above, do not forget that the matrix entry a₁₁ should be always related to the array element a[0][0] in your program.

I'll do the first question for you as it's very easy and may help you to do the second:

using System;

class Program

{

static void Main()

{

double[,] matrix = new double[2,2]{ {0, 1}, {2, 3} };

AddAverage(matrix);

// check it worked

foreach(double d in matrix) Console.WriteLine(d);

Console.ReadKey();

}

static void AddAverage(double[,] matrix)

{

double total = 0;

foreach(double d in matrix) total += d;

double average = total/matrix.Length;

for(int i = 0; i < matrix.GetLength(0); i++)

{

for(int j = 0; j < matrix.GetLength(1); j++)

{

matrix[i, j] += average;

}

}

I'd like to see you have a go at the second question yourself and help you if you get stuck. You'll get no benefit out of it otherwise. However, no-one can do it without knowing how S is calculated!

BTW, are you sure that these questions are to be programmed in C# and not some other language such as C/C++?

The reason I asked is that the question refers to a 2D array as a[0][0]. That is the syntax for a jagged 2D array in C#, not a rectangular 2D array (or matrix).

1 Reply

Know the answer? Post it — somebody with the same question will find it here.

Vulpes14y ago
I'll do the first question for you as it's very easy and may help you to do the second:

using System;

class Program
{
static void Main()
{
double[,] matrix = new double[2,2]{ {0, 1}, {2, 3} };
AddAverage(matrix);

// check it worked
foreach(double d in matrix) Console.WriteLine(d);
Console.ReadKey();
}

static void AddAverage(double[,] matrix)
{
double total = 0;
foreach(double d in matrix) total += d;
double average = total/matrix.Length;

for(int i = 0; i < matrix.GetLength(0); i++)
{
for(int j = 0; j < matrix.GetLength(1); j++)
{
matrix[i, j] += average;
}
}
}
}

I'd like to see you have a go at the second question yourself and help you if you get stuck. You'll get no benefit out of it otherwise. However, no-one can do it without knowing how S is calculated!

BTW, are you sure that these questions are to be programmed in C# and not some other language such as C/C++?

The reason I asked is that the question refers to a 2D array as a[0][0]. That is the syntax for a jagged 2D array in C#, not a rectangular 2D array (or matrix).