Is there any way to avoid unconscious adding alphabet to the code while working on it?

It happened to me many times:

I am working on a long code and sometimes keyborad is touched by pen, hand or .. unconsciously typing some alphabtte even one letter to the code which sometimes is a headache to figure out it was only one extra e.g. ''i''.

Any way to avoid this?

[Adam Danz]

Typos in code are common. A typo should break your code and the error message would indicate an unfamiliar variable or function name such as

x = 1:5; 
y = x.^2;
pllot(x,y, 'o')

% ERROR
Unrecognized function or variable 'pllot'. 

% -OR-
mass = randi(100,1,20); 
accel = sort(rand(1,20)); 
velocity = mass .* accel; 
velAvg = mean(velosity); 

% ERROR
Unrecognized function or variable 'velosity'. 

If you're using smart variable names, the typo should be obvious when you see it. "velosity" in my example above is recognizeable.

A typo shouldn't convert a unique variable name into a duplicate. For example, this code below would not cause an error and the typo would be very difficult to find because of the horrible variable names.

% Bad variable names!
ti = 5; 
tii = 6; 

ti+tii/tii
%        ^oops that was supposed to be ti

This is a problem concerning variable names, not so much typos.

[John D'Errico]

Be more careful?

How can a computer know that somehow one keystroke is something you really wanted to do, and another is a complete accident?

Personally, I'd like the editor to catch when I make any logical or mathematical error in my code. Hmm, better yet, it should know what I want to write, without my even typing a single keystroke. What I should have written, if I were a better programmer?

Why do I find these last ideas a bit chilling?

Yes, the editor is actually pretty smart. mlint catches some things. It can suggest if there are some problems in variable or function names. But best is just to be careful.

[Adam Danz]

and checkcode()

https://www.mathworks.com/help/matlab/ref/checkcode.html