C# Program to Add Two Matrices

Firstly, set three arrays.

int[, ] arr1 = new int[20, 20];
int[, ] arr2 = new int[20, 20];
int[, ] arr3 = new int[20, 20];

Now users will enter values in both the matrices. We have to set the row and size columns as n=3, since we want a square matrix of 3x3 size i.e 9 elements.

Add both the matrices and print the third array that has the sum.

for(i=0;i<n;i++)
for(j=0;j<n;j++)
arr3[i,j]=arr1[i,j]+arr2[i,j];

The following is the complete code to add two matrices in C#.

Example

 Live Demo

using System;
public class Exercise19 {
   public static void Main() {
      int i, j, n;
      int[, ] arr1 = new int[20, 20];
      int[, ] arr2 = new int[20, 20];
      int[, ] arr3 = new int[20, 20];
      // setting matrix row and columns size
      n = 3;
      Console.Write("Enter elements in the first matrix:
");
      for (i = 0; i < n; i++) {
         for (j = 0; j < n; j++) {
            arr1[i, j] = Convert.ToInt32(Console.ReadLine());
         }
      }
      Console.Write("Enter elements in the second matrix:
");
      for (i = 0; i < n; i++) {
         for (j = 0; j < n; j++) {
            arr2[i, j] = Convert.ToInt32(Console.ReadLine());
         }
      }
      Console.Write("
First matrix is:
");
      for (i = 0; i < n; i++) {
         Console.Write("
");
         for (j = 0; j < n; j++)
         Console.Write("{0}\t", arr1[i, j]);
      }
      Console.Write("
Second matrix is:
");
      for (i = 0; i < n; i++) {
         Console.Write("
");
         for (j = 0; j < n; j++)
         Console.Write("{0}\t", arr2[i, j]);
      }
      for (i = 0; i < n; i++)
      for (j = 0; j < n; j++)
      arr3[i, j] = arr1[i, j] + arr2[i, j];
      Console.Write("
Adding two matrices: 
");
      for (i = 0; i < n; i++) {
         Console.Write("
");
         for (j = 0; j < n; j++)
         Console.Write("{0}\t", arr3[i, j]);
      }
      Console.Write("

");
   }
}

Output

Enter elements in the first matrix:
Enter elements in the second matrix:

First matrix is:

000
000
000
Second matrix is:

000
000
000
Adding two matrices:

000
000
000