I can't plot square or rectangle correctly

x = input('enter x number:')
y = input('enter y number:')
z = input('enter widht:')
v = input('enter lenght:')
axes('NextPlot', 'add','XLim', [((-abs(x)-abs(z))+25), ((abs(x)+abs(z)+25))], 'YLim', [((-abs(y)-abs(v))+25), ((abs(y)+abs(v)+25))]);
for e = x:0.5:(abs(x)+abs(z))
plot(e, y, '*k')
pause(0.05)
end
for e = y:0.5:(abs(y)+abs(v))
plot(x,e, '*k')
pause(0.05)
end
for e = x:0.5:(abs(x)+abs(z))
plot(e,(abs(y)+abs(v)),'*k')
pause(0.05)
end
for e = y:0.5:(abs(y)+abs(v))
plot((abs(y)+abs(v)),e, '*k')
pause(0.05)
end
There is a issue with my last for-end loop. Last edge of rectangle doesn't fit correctly. Also I used 25 to see graph more clear. Can you check that. I feel like I did something wrong there too.

 Accepted Answer

Right off the bat, the xlim and ylim were way off in the weeds (at least for the parameters i chose). Try these changes:
% use meaningful descriptions
x = input('enter x offset: ')
y = input('enter y offset: ')
w = input('enter width: ')
h = input('enter height: ')
% filter these once instead of a bunch of times
w=abs(w);
h=abs(h);
clf
% here, i'm adding [h/2 w/2] margin around the box
% that's just something arbitrary i picked
axes('NextPlot', 'add','XLim', [x-w/2 x+w+w/2], 'YLim', [y-h/2 y+h+h/2]);
% why are you using abs(x) and abs(y) everywhere?
% that makes the size wrong if x or y is negative
% if x and y must be non-negative, filter them first, like with w and h
for e = x:0.5:(x+w)
plot(e, y, '*k')
pause(0.05)
end
for e = y:0.5:(y+h)
plot(x,e, '*k')
pause(0.05)
end
for e = x:0.5:(x+w)
plot(e,y+h,'*k')
pause(0.05)
end
for e = y:0.5:(y+h)
plot(y+h,e, '*k')
pause(0.05)
end

3 Comments

Thank you for answer but last edge does not fit again. I used abs because on my homework I need to create axes a followiing rule. For instance I set x (where rectangle starts) -5 and set the length 10. So x axes must be between -15 to 15. Same for y.
Auugh my bad. I was using unity aspect ratio, so I didn't catch that.
for e = y:0.5:(y+h)
plot(x+w,e, '*k')
pause(0.05)
end
If there are some odd requirements for calculating the plot area, then you'll have to follow whatever you're being told to use for calculating xlim and ylim. That said, if [y x] is the location of one corner and [y+h x+w] is the other corner, then you don't need abs() in the loops anywhere.

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R2020b

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Asked:

on 27 Mar 2021

Commented:

on 27 Mar 2021

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