I'm in intro to Java, Can you help me write the next programs in printf please.

(Sum elements column by column) Write a method that returns the sum of all the elements in a specified column in a matrix using the following header: public static double sumColumn(double[][] m, int columnIndex) .Write a test program that reads a 3-by-4 matrix and displays the sum of each column. Here is a sample run:

Enter a 3-by-4 matrix row by row:

1.5 2 3 4

5.5 6 7 8

9.5 1 3 1

Sum of the elements at column 0 is 16.5

Sum of the elements at column 1 is 9.0

Sum of the elements at column 2 is 13.0

Sum of the elements at column 3 is 13.0

Second program please only use printf for all printings

(Sum the major diagonal in a matrix) Write a method that sums all the numbers in the major diagonal in an n * n matrix of double values using the following header: public static double sumMajorDiagonal(double[][] m) Write a test program that reads a 4-by-4 matrix and displays the sum of all its elements on the major diagonal. Here is a sample run:

Enter a 4-by-4 matrix row by row:

1 2 3 4.0

5 6.5 7 8

9 10 11 12

13 14 15 16

Sum of the elements in the major diagonal is 34.5