Matrix multiplication - C++

Vote count:

1

void power(int a[][21], int n, int d)
{
    int e[21][21], k, i, j, l;

    if(d==1)
    {
         for(i=1;i<=n;i++)
        {
            for(j=1;j<=n;j++)
            {
                cout<<a[i][j]<<" ";
            }
            cout<<endl;
        }

    }
    else
    {

    for(i=1;i<=n;i++)
    {
        for(j=1;j<=n;j++)
        {
            e[i][j]=0;
        }
    }

    for(l=1;l<d;l++)
        {
            for(i=1;i<=n;i++)
            {
                for(j=1;j<=n;j++)
                {
                    for(k=1;k<=n;k++)
                    {
                        e[i][j]=e[i][j]+(a[i][k]*a[k][j]);
                    }
                }
            }
        }

    for(i=1;i<=n;i++)
        {
            for(j=1;j<=n;j++)
            {
                cout<<e[i][j]<<" ";
            }
            cout<<endl;
        }
    }

}

I am trying to build a function that calculates the power of a matrix. The program works for the 1st and 2nd power of the matrix but if I want to calculate the 3rd power the function will return incorrect values. I think the problem is at retaining the previous results but I can't figure out on how to fix it.

asked 3 mins ago

Vlad

23

Matrix multiplication - C++