title: some issue in my prolog code
body: <p>i am new to prolog and have written some code in prolog simply to show some message but when i run it produce some error that : </p>
  
  <p>1) Syntax error: Unexpected end of clause</p>
  
  <p>2)ERROR: Syntax error: Operator expected
  ERROR: 
  ERROR: ** here **
  ERROR: .course_crh .</p>
  
  <p><strong>Here is my code</strong></p>
  
  <pre><code>gpa(0).
  gpa(0.1).
  gpa(0.2).
  gpa(0.3).
  gpa(0.4).
  gpa(0.5).
  gpa(0.6).
  gpa(0.7).
  gpa(0.8).
  gpa(0.9).
  gpa(1.0).
  gpa(1.1).
  gpa(1.2).
  gpa(1.3).
  gpa(1.4).
  gpa(1.5).
  gpa(1.6).
  gpa(1.7).
  gpa(1.8).
  gpa(1.9).
  gpa(2.0).
  gpa(2.1).
  gpa(2.2).
  gpa(2.3).
  gpa(2.4).
  gpa(2.5).
  gpa(2.6).
  gpa(2.7).
  gpa(2.8).
  gpa(2.9).
  gpa(3.0).
  gpa(3.1).
  gpa(3.2).
  gpa(3.3).
  gpa(3.4).
  gpa(3.5).
  gpa(3.6).
  gpa(3.7).
  gpa(3.8).
  gpa(3.9).
  gpa(4.0).
  course_crh(gpa(X)):-
  write('Please Enter gpa'),
  read(X),
  (( X&gt;=2.0, X=&lt;4.0)-&gt;
  write('Max 18 credit are allowed');write('Less than 18 credit hrs allowed').
  </code></pre>
  
  <p><strong>What i want</strong></p>
  
  <p>that calling on course_crh() it print the message to enter gpa then check in condition and print the final message depends on my input value.</p>
  
  <p>i have tried this 
  <a href="https://stackoverflow.com/questions/30830979/use-of-conditionals-in-prolog">Use of conditionals in Prolog</a>
  and
  this <a href="https://stackoverflow.com/questions/26003045/conditional-statements-in-prolog">Conditional Statements in Prolog</a></p>
  
  <p>but failed again and again</p>