问Java:主对角线之上和下面形成的三角形元素之和

EN

   public static void main(String...args) {

       Scanner scanner = new Scanner(System.in);
       System.out.print("Enter rows/cols : ");    //rows and 
      columns in matrix must be same.
       int rows = scanner.nextInt();
       int columns=rows;
       int[][] matrix = new int[rows][rows];

       System.out.println("Elements of matrix :");
       for (int i = 0; i < rows; i++) {
              for (int j = 0; j < columns; j++) {
                    matrix[i][j] = scanner.nextInt();
              }
       }

       //Logic to calculate sum of elements above diagonal.
       int sum=0;
       for (int j = 1; j < columns; j++) {
              for (int i=j-1 ; i>=0 ; i--) {
                    sum= sum + matrix[i][j];
              }

       }

       int sumBelow=0;
       for (int i = 1; i < rows; i++) {
              for (int j=i-1 ; j>=0 ; j--) {
                    sumBelow= sumBelow+ matrix[i][j];
              }

       }

       System.out.println("\Matrix is : ");
       for (int i = 0; i < rows; i++) {
              for (int j = 0; j < columns; j++) {
                    System.out.print(matrix[i][j] + " ");
              }
              System.out.println();
       }

       System.out.println("sum above: "+sum);
       System.out.println("suma below: " + sumBelow );

       int subtract;
       if(sum > sumBelow) {
           razlika = sum - sumBelow;
           System.out.println("Subtracted: " + subtract);
       }else {
           subtract= sumBelow- sum;
           System.out.println("Subtracted: " + subtract);

       }



}