Add Two Matrix Using Multi-Dimensional Arrays in C++

A matrix is a rectangular array of numbers that is arranged in the form of rows and columns.

An example of a matrix is as follows.

A 4*3 matrix has 4 rows and 3 columns as shown below −

3 5 1
7 1 9
3 9 4
1 6 7

A program that adds two matrices using multidimensional arrays is as follows.

Example

 Live Demo

#include <iostream>
using namespace std;
int main() {
   int r=2, c=4, sum[2][4], i, j;
   int a[2][4] = {{1,5,9,4} , {3,2,8,3}};
   int b[2][4] = {{6,3,8,2} , {1,5,2,9}};
   cout<<"The first matrix is: "<<endl;
   for(i=0; i<r; ++i) {
      for(j=0; j<c; ++j)
      cout<<a[i][j]<<" ";
      cout<<endl;
   }
   cout<<endl;
   cout<<"The second matrix is: "<<endl;
   for(i=0; i<r; ++i) {
      for(j=0; j<c; ++j)
      cout<<b[i][j]<<" ";
      cout<<endl;
   }
   cout<<endl;
   for(i=0;i<r;++i)
   for(j=0;j<c;++j)
   sum[i][j]=a[i][j]+b[i][j];
   cout<<"Sum of the two matrices is:"<<endl;
   for(i=0; i<r; ++i) {
      for(j=0; j<c; ++j)
      cout<<sum[i][j]<<" ";
      cout<<endl;
   }
   return 0;
}

Output

The first matrix is:
1 5 9 4
3 2 8 3

The second matrix is:
6 3 8 2
1 5 2 9

Sum of the two matrices is:
7 8 17 6
4 7 10 12

In the above program, first the two matrices a and b are defined. This is shown as follows.

int a[2][4] = {{1,5,9,4} , {3,2,8,3}};
int b[2][4] = {{6,3,8,2} , {1,5,2,9}};
cout<<"The first matrix is: "<<endl;
for(i=0; i<r; ++i) {
   for(j=0; j<c; ++j)
   cout<<a[i][j]<<" ";
   cout<<endl;
}
cout<<endl;
cout<<"The second matrix is: "<<endl;
for(i=0; i<r; ++i) {
   for(j=0; j<c; ++j)
   cout<<b[i][j]<<" ";
   cout<<endl;
}

The two matrices are added using a nested for loop and the result is stored in matrix sum[][]. This is shown in the following code snippet.

for(i=0;i<r;++i)
for(j=0;j<c;++j)
sum[i][j]=a[i][j]+b[i][j];

After the sum of the two matrices is obtained, it is printed on screen. This is done as follows −

cout<<"Sum of the two matrices is:"<<endl;
for(i=0; i<r; ++i) {
   for(j=0; j<c; ++j)
   cout<<sum[i][j]<<" ";
   cout<<endl;
}