title: C++ Belong Condition
body: <p>I need to do an if condition with ∉ (not belong to)</p>
  
  <p>The condition:</p>
  
  <pre><code>if tj ∉ A(fi) where A(fi) contains some elements
  </code></pre>
  
  <p>Example:</p>
  
  <pre><code>A(f1)= t1, t2 A(f2)= t1, t3
  </code></pre>
  
  <p>so if t3 ∉ A(f1) do something.</p>
  
  <p>My problem is I don't know how to do the ∉ in C++</p>
  
  <p><strong>EDIT:</strong></p>
  
  <p>Thank you for the answers.</p>
  
  <p>I have one more questions but I don't know if it's really possible or if I dream too much. I need to run my program many times but each time the elements inside the A(fi) will change.</p>
  
  <p>I know it's possible to do random with 0 and 1. So I was thinking that instead of put t1 it will be replace by 0 or 1 but after I don't know how to write the order.</p>
  
  <p>Like I have A(f1) ={1, 0,1,0} and A(f2)={0,1,1,0} so t1 appear in A(f1), t2 appear in A(f2), t3 appear in A(f1) and A(f2) and so on.</p>
  
  <p>For the set function it writes:</p>
  
  <p>"Sets are containers that store unique elements following a specific order." So it might be possible to give a name to the order</p>
  
  <p>So my question is do you think is it possible and how I can link t1, t2, t3...?</p>
  
  <p>I find another problem is that I might to create more set to have more than 2 or A(fi), the number is not in advance. I didn't find how is it possible to create a different number of set at different time. is it possible? </p>