Sum of all the elements after the matrix diagonal

Hello. I am trying to calculate the total sum of all the elements in any given matrix, including row array and column array, starting from the cell where the row index is equal to column index (matrix diagonal). I am picking up an extra value in my code, and I don't know why. Here is my code:

(function syntax with a matrix given)

(getting the number of the elements in the matrix using the "size" function)

(initializing my output count "answer")

for r = 1:row
    for c = 1:col
        if col >= row
            answer = col + answer;
        end
    end
end

So for a matrix A [1 2 3; 4 5 6; 7 8 9], the answer should be 26 and I am getting 27 and I can't figure why. I've tried to use the "sum" function but it gets just way to complicated and I get lost with referencing of the columns/rows. Also I must use the "for loop" and no super fancy build-in functions.

[Matt J]

Also I must use the "for loop" and no super fancy build-in functions.

It is absurd to call this "super fancy",

>> sum(  triu(A), 'all')

ans =

    26

[Dmitriy]

Thanks Matt, but:

"Assessment result: incorrect [1 2 3; 4 5 6; 7 8 9]

The submission must not contain the following functions or keywords: triu"

That's why said "no super fancy build-in functions". I wish I could use them but the solution must be based on "for... loop" function only.

Answer 1

[Matt J]

answer=0;
for r = 1:row
    for c = 1:col
        if c >= r
            answer = A(r,c) + answer;
        end
    end
end

answer =

    26

[Ameer Hamza]

I guess the OP might be initializing the variable answer with 1. That will also make the final sum 27.

[Matt J]

No, the original code initialized with answer=0 will give 27.

[Ameer Hamza]

Oh! Coincidently the final sum was also close to 26.

[Matt J]

Yes, an unfortunately misleading test case.

[Dmitriy]

That's the code I wrote in the first 15 minutes of thinking about the problem, but I was getting the wrong answers with it, so I abondoned the idea completly.

P.S. I ran your code and found out that I had previously the iverted logic and that's why mine didn't work. Thanks, man! Problem solved.