title: "Error: Conflicting with its use here as the name of a function" when using += operator
body: <p>File abc.m has</p>
  
  <pre><code>function [] = abc(N)
      N += 1;
  </code></pre>
  
  <p>When I try to execute abc by passing any number (e.g. 5) for N, I get the error 
  "N" was previously used as a variable, conflicting with its use here as the name of a function. 
  It gives the error in the line N += 1;</p>
  
  <p>But I do not understand where I am using N as a function name.</p>