DiagonalMatrix.java

class GFG  
{ 
    static int MAX = 100; 
  
    // Function to print the Principal Diagonal 
    static void printPrincipalDiagonal(int mat[][], int n) 
    { 
        System.out.print("Principal Diagonal: "); 
  
        for (int i = 0; i < n; i++) 
        { 
            for (int j = 0; j < n; j++)  
            { 
  
                // Condition for principal diagonal 
                if (i == j) 
                { 
                    System.out.print(mat[i][j] + ", "); 
                } 
            } 
        } 
        System.out.println(""); 
    } 
  
    // Function to print the Secondary Diagonal 
    static void printSecondaryDiagonal(int mat[][], int n) 
    { 
        System.out.print("Secondary Diagonal: "); 
  
        for (int i = 0; i < n; i++)  
        { 
            for (int j = 0; j < n; j++)  
            { 
  
                // Condition for secondary diagonal 
                if ((i + j) == (n - 1))  
                { 
                    System.out.print(mat[i][j] + ", "); 
                } 
            } 
        } 
        System.out.println(""); 
    } 
  
    // Driver code 
    public static void main(String args[]) 
    { 
        int n = 4; 
        int a[][] = {{1, 2, 3, 4}, 
                     {5, 6, 7, 8}, 
                     {1, 2, 3, 4}, 
                     {5, 6, 7, 8}}; 
  
        printPrincipalDiagonal(a, n); 
        printSecondaryDiagonal(a, n); 
    } 
}