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

Question

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

Explanation / Answer

// Note: One question at a time please -- Policy of Chegg

import java.util.Scanner;
class Main {
public static double sumColumn(double[][] m, int columnIndex)
{
// declaring varialbe to 0
double sum = 0;
  
// looping through each row
for(int i=0; i<m.length; i++)
{
// adding the value to the sum
sum += m[i][columnIndex];
}
  
// returning the sum
return sum;
}
public static void main(String[] args) {
  
// declaring variables
int i,j;
double[][] matrix = new double[3][4];
Scanner sc = new Scanner(System.in);
  
// taking user input of matrix
System.out.println("Enter a 3-by-4 matrix row by row:");
for(i=0; i<3; i++)
{
for(j=0; j<4; j++)
{
matrix[i][j] = sc.nextDouble();
}
}
  
// calling for each column
for(i=0; i<4; i++)
{
System.out.printf("Sum of the elements at column %d is %.1f ",i,sumColumn(matrix, i));
}
}
}

/* SAMPLE OUTPUT
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
*/

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