Source code to multiply two matrix in C++ programming

Source code to multiply two matrix in C++ programming

#include <iostream>
using namespace std;
int main()
{
    int a[10][10], b[10][10], mult[10][10], r1, c1, r2, c2, i, j, k;
    cout << "Enter rows and columns for first matrix: ";
    cin >> r1 >> c1;
    cout << "Enter rows and columns for second matrix: ";
    cin >> r2 >> c2;

/* If colum of first matrix in not equal to row of second matrix, asking user to enter the size of matrix again. */
    while (c1!=r2)
    {
        cout << "Error! column of first matrix not equal to row of second.";
        cout << "Enter rows and columns for first matrix: ";
        cin >> r1 >> c1;
        cout << "Enter rows and columns for second matrix: ";
        cin >> r2 >> c2;
    }

/* Storing elements of first matrix. */
    cout << endl << "Enter elements of matrix 1:" << endl;
    for(i=0; i<r1; ++i)
    for(j=0; j<c1; ++j)
    {
        cout << "Enter element a" << i+1 << j+1 << " : ";
        cin >> a[i][j];
    }

/* Storing elements of second matrix. */
    cout << endl << "Enter elements of matrix 2:" << endl;
    for(i=0; i<r2; ++i)
    for(j=0; j<c2; ++j)
    {
        cout << "Enter element b" << i+1 << j+1 << " : ";
        cin >> b[i][j];
    }

/* Initializing elements of matrix mult to 0.*/
    for(i=0; i<r1; ++i)
    for(j=0; j<c2; ++j)
    {
       mult[i][j]=0;
    }

/* Multiplying matrix a and b and storing in array mult. */
    for(i=0; i<r1; ++i)
    for(j=0; j<c2; ++j)
    for(k=0; k<c1; ++k)
    {
        mult[i][j]+=a[i][k]*b[k][j];
    }

/* Displaying the multiplication of two matrix. */
    cout << endl << "Output Matrix: " << endl;
    for(i=0; i<r1; ++i)
    for(j=0; j<c2; ++j)
    {
        cout << " " << mult[i][j];
        if(j==c2-1)
            cout << endl;
    }
    return 0;
}

Output

Enter rows and column for first matrix: 3
2
Enter rows and column for second matrix: 3
2
Error! column of first matrix not equal to row of second.

Enter rows and column for first matrix: 2
3
Enter rows and column for second matrix: 3
2

Enter elements of matrix 1:
Enter elements a11: 3
Enter elements a12: -2
Enter elements a13: 5
Enter elements a21: 3
Enter elements a22: 0
Enter elements a23: 4

Enter elements of matrix 2:
Enter elements b11: 2
Enter elements b12: 3
Enter elements b21: -9
Enter elements b22: 0
Enter elements b31: 0
Enter elements b32: 4

Output Matrix:
24 29
6  25