Am beginner here, can anyone tell me What is wrong with the code with while loop?

The following code is a simplified version of my problem. Can anyone pointout why the loop is not terminating??

x=2;
y=2;
a=[x,y];
b=[10,10];
tf=isequal(a,b);
while tf==0
    x=x+1;
    y=y+1;
    tf=isequal(a,b);
end
disp(a);

Answer 1

[James Tursa]

You never update the "a" vector inside the loop. It was built from the original values of x and y and never changes. To fix this:

while tf==0
  x=x+1;
  y=y+1;
  a=[x,y]; % <-- add this line
  tf=isequal(a,b);
end

[akash sonnad]

But the same code is not working with decimal increments

if true
  % code
end
x=0.1;
y=0.1;
a=[x,y];
b=[0.2,0.2];
tf=isequal(a,b);
while tf==0
   x=x+0.01;
   y=y+0.01;
   a=[x,y]
   tf=isequal(a,b);
end
disp(a);

[James Tursa]

Because floating point arithmetic with fractional values is in general not exact. See this article:

http://matlab.wikia.com/wiki/FAQ#Why_is_0.3_-_0.2_-_0.1_.28or_similar.29_not_equal_to_zero.3F

[Stephen23]

"But the same code is not working with decimal increments"

Because the accumulated floating point error means that those values are NOT the same. See the answers to your later question:

https://www.mathworks.com/matlabcentral/answers/403393-i-have-this-code-which-is-behaving-differently-for-decimal-and-integer-values-where-am-i-missing