how to get rid of the too many arguments error for "and" while keeping output the same

y = nthroot(a,3);
a = 0; 
b = 2;
xold = a;
for i = 1 - 100 
    set x = (a + b)/2;
    a = 2 + s;
    if abs(x-xold) < 10^-8 
        then % checking required accuracy
        FoundSolution = true; % done
        Break; % leave for environment
    end
    if f(a) < 0
        then a = a and b = x;
    else 
        a = x and b = b;
    end 

Not sure how to get rid of the too many arguments error for "and"

[Les Beckham]

This code isn't even close to valid Matlab syntax. There are no then or set keywords in Matlab, for example. Also, the normal way to do a logical and of two conditions is with the operator &&. There is a spelled out and but it is a function and is called like this result = and(a,b) where a and b are the conditions like x < 0, for example.

If you are a beginner in using Matlab, I would suggest taking a couple of hours to go through the free tutorial that can be found here: Matlab Onramp

[Walter Roberson]

set x = (a + b)/2;

In MATLAB, that would look for a function named set and would invoke that function passing in the arguments

'x'
'='
'(a + b)/2'

likewise

then a = a and b = x

would look for a function named then and would call it as

then('a', '=', 'a', 'and', 'b', '=', 'x')

There just happens to be a method named then in toolbox/matlab/connector2/common/+connector/+internal/Future.p

Answer 1

[John D'Errico]

If you write invalid MATLAB synrtax, then you need to expect your code to fail. Perhaps some of those lines might be valid in other languages, but in MATLAB, expect problems. For example:

for i = 1 - 100

while that line will not overtly fail, it does NOT generate a loop from 1 to 100. Instead, it will set i to the number -99, not even iterating. If you wanted your code to perform a loop from 1 to 100, then write this:

for i = 1:100 

Next, we see:

set x = (a + b)/2;

Again, this does not fail directly, because set is an existing MATLAB function. So it tries to use the function set, as a command. But set is not how you assign a value to some variable. Just do this instead:

x = (a + b)/2;

Next we see:

then % checking required accuracy

If statements don't have a then clause. So that line is just a no-op, that does nothing except generate a syntactical problem. The same applies to this line:

then a = a and b = x;

Again, then is meaningless because of the then. I'm not at all sure what you intended with a = a, since that is indeed a no-op, that does noting except toss CPU sybles in the bit bucket. But worse, you also used and. And is not a connector that tells MATLAB to execute two statements on one line.

It looks like you are still writing code in some other language. I won't try to guess which one. But languages have their own syntax. Fail to follow it, or hope that syntax which might be valid for some other language is valid syntax in MATLAB? Then expect to see random garbage for results.