how to use abs function in this code?

%Write a Matlab script to create random integer matrix with elements between -30 and 30. 
%The size of the matrix must be first be read from user input. Use loops to sum of each row. 
%Then find the differences between all pairs of these sums. 

a=input('Enter the size of rows:');
b=input('Enter the size of columns:');
A=randi([-30 30],a,b)
r=zeros(a);
d=zeros(a);
for i=1:a
    for j=1:b
    r(i)=r(i)+A(i,j);
    end
end
for k=1:a
    for l=1:a
     d(k,l)=(r(k)-r(l));   
    end
end
difference=triu(d,1)

%So I write this code and it worked -with a problem-. Let's say I created a 2x2 Matrix. 
%TheSumOfFirstRow=2, TheSumOfSecondRow=3. As the result I wanna see both 2-3=-1 and 3-2=1.
%But the code that I wrote calculates just 2-3=-1.

Can someone please help :)

Answer 1

[KALYAN ACHARJYA]

a=input('Enter the size of rows:');
b=input('Enter the size of columns:');
A=randi([-30 30],a,b)
r=zeros(a);
d=zeros(a);
for i=1:a
    for j=1:b
    r(i)=r(i)+A(i,j);
    end
end
for k=1:a
    for l=1:a
     d(k,l)=abs((r(k)-r(l)));   
    end
end
difference=triu(d,1)

[Ozan Mirzanli]

thank you, i tried this already but this only changes the result to positive. i want them both to be in answer. like -n and +n

[KALYAN ACHARJYA]

Then what actually you are trying to do?

Is this?

a=input('Enter the size of rows:');
b=input('Enter the size of columns:');
A=randi([-30 30],a,b)
sum_row=zeros(1,a);
for i=1:a
    sum_row(i)=sum(A(i,:));
end
for k=1:length(sum_row)-1
   d(k)=sum_row(k+1)-sum_row(k);
end
d(end)=sum_row(end)-sum_row(1);
Difference=d

[Ozan Mirzanli]

This is our matrix

A =

-14 9

11 -21

This is the result due to your second code

Difference =

-5 15

15 -5

This is the result how it should be

Difference =

5 (Sum of Row 1 - Sum of Row 2)

-15 (Sum of Row 2 - Sum of Row 1)

The sentences in parantheses are not gonna be in the result, I write them to explain what I exactly mean.

[Ozan Mirzanli]

any ideas?