MATLAB Function Takes as Input Two Positive Integers and Returns a Matrix

Write a MATLAB function that takes as input two positive integers and returns a matrix. Given positive integers m and n, hw21 creates an m x n array A whose elements consist of the first mn positive integers stored in A as follows: the first column of A consists of the first m consecutive positive integers given in order from 'top to bottom', the second column of A (if it exists) consists of the next m consecutive positive integers given in order from 'bottom to top', and continues filling in the columns in order with the next m consecutive positive integers by alternating between 'top to bottom' and 'bottom to top' until all columns are filled in.

So far I have a small program written but I stuck with what to do next. I dont know what to put in 'A = ?', so I am asking for assistance on how to get started. Heres what I have:

function A = hw21(m,n)

%

[NRows, NCols] = size(A);

number = 0

for col = 1:NCols

for row = NRows:1

A = ?;

number = number + 1;

end

end

[Sophie Culhane]

I now have this program which is more developed, but still does not work. Any ideas on how to progress?

function A = hw21(m,n)

%

NRows = m;

NCols = n;

A = zeros(NRows, NCols)

number = 0;

for col = 1:NCols

number = number + 1;

even = fix(col/2);

if even == col/2

for row = NRows:1:1

A(row,col) = A(row,col) + number;

end

else

for row = 1:NRows

A(row,col) = A(row,col) + number;

end

end

end

[Sophie Culhane]

I also added 'number = number + 1;' after 'A(row,col) = A(row,col) + number;' in both areas.

Answer 1

[Ameer Hamza]

Since this is a homework problem so I won't give you a direct solution but following will give you hints.

You need to have a different order of elements for even and odd columns. To check if the current value of col is even or odd, see the rem() function. Then you can write two for-loops for even and odd column.

Also, use row and cols as indexes of matrix A.

Here is a general sketch.

function A = hw21(m,n)
%
[NRows, NCols] = size(A);
number = 0
for col = 1:NCols
    number = number + 1;
    iseven = rem(col, ???) % check if if it is even or odd
    if iseven
        for row = NRows:1
            A(row, col) = ?; % think what should you assign here at this row and col position
        end
    else
        for row = 1:NRows
            A(row, col) = ?; % think what should you assign here at this row and col position
        end
    end
    
end

[Sophie Culhane]

We have yet to learn to command 'rem' in class and therefore cannot use it on the program. Is there another way I can do this without the command?

[Ameer Hamza]

Here is another test for even

iseven = floor(col/2)==col/2;

[Walter Roberson]

mod() or floor() can be used.