**The below problem is to find the kth power of a matrix.**

Code:

#include<iostream>
using namespace std;
int main()
{
double **a;
int r,k;
double **matrixExpon(double**,int);
cout<<"the no of rows in the matrix is"<<endl;
cin>>r;
a=new double*[r];
for(int i=0;i<r;i++)
{
a[i]=new double(r);
}
cout<<"Value of k is "<<endl;
cin>>k;
for(int i=1;i<k;i++)
a=matrixExpon(**a,r);
}
double **matrixExpon(double **a,int r)
{
double **b;
b=new double *[r];
int i;
for(i=0;i<r;i++)
{
b[i]=new double [r];
}
int j,k,sum=0;
for(i=0;i<=r;i++)
{
for(j=0;j<=r;j++)
{
for(k=0;k<=r;k++)
sum=sum+a[i][k]*a[k][j];
b[i][j]=sum;
sum=0;
}
}
return b;
}

**Compilation Error :**

cannot convert ‘double’ to ‘double**’ for argument ‘1’ to ‘double** matrixExpon(double**, int)’|

please help here..