Non working while loop

When running the code below it seems the while loop is run through once and then executes the commands after the last end statement and ends the program.

I do not understand while the loop doesn’t actually loop until the while loop statement isn't true.

Thank you in advance

function P=fixpointiteration(val)

switch nargin

case 0

disp('0 Chosen input')

x0 = rand;

case 1

disp('1 Chosen input')

x0 = val;

otherwise

error('Unexpected input')

end

disp(x0)

f = @(x0) cos(x0);

i=0;

t = 0.00001;

x1=1;

while abs (x1-x0)>t

i=i+1

x1 = f(x0)

fprintf('x%d = %.8f\n',i,x1)

x0 = x1

end

disp('Number of iterations: ')

disp(i)

Answer 1

[Voss]

The last line inside the while loop:

 x0 = x1

sets x0 to x1. Therefore, when the while condition is checked again (which happens immediately), x1 and x0 are equal, so abs(x1-x0) is 0, which is not greater than t, so the loop stops iterating.

[Mikael Freyhult]

I moved the x0 = x1 expression to above the x1 = f(x0) expression and now it works.

Thank you!