Coding untuk membuat perhitungan Matriks

import java.io.*;
class determinan
{
public static void main (String [] args) throws Exception
{
System.out.println ("==========================");
System.out.println (" Determinan Matriks");
System.out.println ("==========================");
BufferedReader input = new BufferedReader (new InputStreamReader(System.in));
System.out.print ("Masukan ordo matriks : ");
int n = Integer.parseInt (input.readLine());
int [][] matrixA = new int [n][n];
int [][] matrixB = new int [n][n];
int [][] matrixC = new int [n][n];
int det;
System.out.print ("\n");
System.out.println ("==========================");
System.out.println (" Input Matrix A");
System.out.println ("==========================");

for (int i=0;i<n; i++)
{
for (int j=0;j<n;j++)
{
System.out.print ("Element ["+(i+1)+","+(j+1)+"] = ");
matrixA[i][j] = Integer.parseInt (input.readLine());
}
}
System.out.print ("\n");
System.out.println ("==========================");
System.out.println (" Matrix A");
System.out.println ("==========================");
for (int i=0;i<n;i++)
{
System.out.print ("| ");
for (int j=0;j<n;j++)
{
System.out.print (matrixA[i][j]+" ");
}
System.out.println ("|");
}
if (n==2)
{
System.out.print ("\n");
System.out.println ("==========================");
det=(matrixA[0][0]*matrixA[1][1])-(matrixA[0][1]*matrixA[1][0]);
System.out.println ("det A = "+det);
System.out.println ("==========================");
System.out.print ("\n");
}
if (n==3)
{
System.out.print ("\n");
System.out.println ("==========================");
det=(matrixA[0][0]*matrixA[1][1]*matrixA[2][2])+(matrixA[0][1]*matrixA[1][2]*matrixA[2][0])+(matrixA[0][2]*matrixA[1][0]*matrixA[2][1])
-(matrixA[2][0]*matrixA[1][1]*matrixA[0][2])-(matrixA[2][1]*matrixA[1][2]*matrixA[0][0])-(matrixA[2][2]*matrixA[1][0]*matrixA[0][1]);
System.out.println ("det A = "+det);
System.out.println ("==========================");
System.out.print ("\n");
}
}
}