why am I getting "Assignment has more non-singleton rhs dimensions than non-singleton subscripts" in this code?

for i=1:x_row ,m=1:magic_row;
    for j=1:x_col , n=1:magic_col;
        if(a<=c)
           % t=x(i,j)+y(m,n);
            if((Str(a)+x(i,j)+y(m,n))>255) 
                temp=x(i,j)+Str(a)+y(m,n)-256;
            else
                temp=x(i,j)+Str(a)+y(m,n);
            end
            z(i,j)=uint8(temp); %this line shows error
        else
            z(i,j)=uint8(x(i,j));
        end
        a=a+1;
    end
end

[Stephen23]

@Ishvarya E: please show us the complete error message. This means all of the red text. Currently we have no idea where the error occurs.

[Ishvarya E]

@Stephen Cobeldick: Thank you. And this is the error message I got.

"Subscripted assignment dimension mismatch.

Error in encrypt (line 32) z(i,j)=uint8(temp);"

Answer 1

[Walter Roberson]

Your lines

for i=1:x_row ,m=1:magic_row;
    for j=1:x_col , n=1:magic_col;

are equivalent to

for i=1:x_row
  m=1:magic_row;
  for j=1:x_col
    n=1:magic_col;

so your m and n are going to end up being vectors, and y(m,n) is going to be a 2D array. That leads to temp being a 2D array, but you are trying to store temp into the single location z(i,j)

There is no way in MATLAB to use a single for loop to change two variables simultaneously. Since your two variables per line appear to be different length, they appear to be varying independently, so you will probably need to go for four nested loops -- or else vectorize.

[Ishvarya E]

@Walter Roberson : Thank you.