C++ Program of Multiplication of Matrix Using 2D Array

In this program we are going to multiply two matrices. For this purpose we will declare two arrays, we will take input in these arrays and then we will multiply them and store their result in a new array.

 

Program:

// Program By http://solutionscpp.blogspot.com
// Author Mansoor Ahmed
// GMail ID: secguy000@gmail.com
 
#include<iostream>
using namespace std;

int main()
{
    int a[10][10], b[10][10], multi[10][10];
    int row1=0, column1=0, row2=0, column2=0;
  
    cout << "Enter rows for the first matrix: ";
    cin >> row1;
  
    cout << "Enter columns for the first matrix: ";
    cin >> column1;
  
  
    cout << "Enter rows for second matrix: ";
    cin >> row2;
  
    cout << "Enter columns for second matrix: ";
    cin >> column2;

/* If columns of first matrix in not equal to rows of second matrix then error will occur, asking user to re-enter size of matrix. */
 
    while (column1!=row2)
    {
  
    cout << "Error Occured! column of first matrix not equal to row of second.";
      
    cout << "Enter rows for the first matrix: ";
    cin >> row1;
  
    cout << "Enter columns for the first matrix: ";
    cin >> column1;
  
  
    cout << "Enter rows for second matrix: ";
    cin >> row2;
  
    cout << "Enter columns for second matrix: ";
    cin >> column2;
  
    }

/* Filling of first matrix. */

    cout<< "Enter elements of 1st matrix: " << endl;
    for(int i=0; i<row1; i++)
    for(int j=0; j<column1; j++)
    {
        cout << "Enter element a" << i+1 << j+1 << " : ";
        cin >> a[i][j];
    }

/* Filling of second matrix. */
    cout <<"Enter elements of 2nd matrix: " << endl;
    for(int i=0; i<row2; ++i)
    for(int j=0; j<column2; ++j)
    {
        cout << "Enter element b" << i+1 << j+1 << " : ";
        cin >> b[i][j];
    }

/* Initializing array of multi.*/
    for(int i=0; i<row1; ++i)
    for(int j=0; j<column2; ++j)
    {
       multi[i][j]=0;
    }

/* Multiplying matrix a and b and storing in array of multi. */
    for(int i=0; i<row1; i++)
    for(int j=0; j<column2; j++)
    for(int k=0; k<column1; k++)
    {
        multi[i][j]=multi[i][j] + a[i][k] * b[k][j];
    }

/* Displaying the result. */
    cout <<"Output Matrix: " << endl;
    for(int i=0; i<row1; i++)
    for(int j=0; j<column2; j++)
    {
        cout << " " << multi[i][j];
        if(j==column2-1)
            cout << endl;
    }
    return 0;
}

Output: