very strange error of for loop

I made this kind structure code

but the result is not I had expecetd

k=1;
for i=1:1:100
  
    if(i==1)
        a=zeros(size(i));
        b=zeros(size(i));
    end
    
    a(k)=sin(i);
    b(k)=a(k)
    k=k+1
end

a(k) display the sin wave

but b(k) dispay only one constant value

like y=3

what happend to my code?

Answer 1

[Star Strider]

You did not include the plot call you are using.

If you are plotting:

figure
plot(a,b)

it will show a straight line from (-1,-1) to (1,1) because both ‘a’ and ‘b’ have the same values.

.

[NoYeah]

yes it has to be same

but my code they are not the same

werid

[Star Strider]

I am using R2020a, and Windows 10.

Is that the only code you are running in that script?

There could be version differences, however I doubt they would be that extreme.

If you run this line:

which plot -all

from your Command Window or a script, all the results should share this part of the path to each (the exact configuration could be operating-system dependent):

C:\Program Files\MATLAB\R2020a\toolbox\matlab\

The rest oif the path will likely vary. If any do not, and it turns out that you have another function named ‘plot’, that could be the problem. (Naming user-defined functions the same as MATLAB built-in functions is called ‘overshadowing’ and is to be avoided.)

Beyond that, I have no idea what the problem could be.

.