In what I missed

function [ val, ea, iter] = IterMeth(x , es, maxit)
%%initialization
iter=12;
val = exp(1);
xr = [ ];
ea =100;
%iterative calculation
while (1)
    xrold=xr;
    xr= xr-x^iter/factorial(iter);                <--------------------------here?
    iter= iter+ 1;
    if xr~=0
    ea=abs((xr-xrold)/xr)*100;
    end
    if ea<=es || iter >= maxit,break,end
end
val=xr;
end

[VBBV]

What is x in IterMeth(x,es,maxit) ? Vector of values or scalar ?

If it's vector of values then use below

%true
xr-x.^iter./factorial(iter)

[KSSV]

What is the problem you are facing? What is the input you trying. Ask your question clearly.

[Saad Almalki]

I fixed the error, but this error will appear again

--------------------------------------------------------

Not enough input arguments.

Error in EX3 (line 16)

if ea<=es || iter >= maxit,break,end

[Walter Roberson]

You appear to be running your function but passing in either only one parameter, or else two parameters. You need to pass in three parameters to your function.

[VBBV]

%true
if ea<=es || iter >= maxit 
   break;
end

Use a semicolon ; not a comma ,

[Walter Roberson]

comma is acceptable syntax there.

    if ea<=es || iter >= maxit,break,end

means the equivalent of

execute the if statement test portion, and display the result. However, an if test does not have any result (and in particular, the result of it is not the value of ea<=es || iter >= maxit so nothing will be displayed

Then, under the condition that the test succeeded, execute the break statement, and display the result. However, a break does not have a result, so nothing will be displayed

Comma acts as a statement separator that does not supress the result of compution... but in this case there is no result of computation to display so it does not matter that you used comma instead of semi-colon.

Something that would be perfectly valid would be

 if iter > 1, iter, end

and that would be the same as

 if iter > 1
     iter
 end

Well, the same except for some rules about exactly when interrupts can occur.

[VBBV]

Ok. Is it same when there is keyword after comma ? In the e.g. you cited its a variable iter which changes values in the program

[VBBV]

%if true
if ea<=es || iter >= maxit,break,end

Give a value to maxit variable before it enter the while loop

Answer 1

[Walter Roberson]

xr = [ ];

That is empty.

    xrold=xr;

so that is empty.

    xr= xr-x^iter/factorial(iter);                %<--------------------------here?

empty minus anything would be empty.

You are passing in x, but if it is not a scalar, you need

    xr = xr - x.^iter ./ factorial(iter);