title: I am unable to understand the error in this code that is preventing an output to be displayed
body: <pre><code>module Calculator(out,a,b,op);
    input [3:0] a,b;
    input [1:0] op;
    output [4:0] out;
  
    reg [32:0] out;
    
    initial
    begin
      case(op)
        2'b00: out &lt;= a+b;
        2'b01: out &lt;= a-b;
        2'b10: out &lt;= a*b;
        2'b11: out &lt;= a/b;
      endcase
      out = a+b;
    end
  endmodule
  
  module test_Calci;
        reg [3:0]a,b;
        reg [1:0] op;
        wire [32:0] out;
        
  Calculator ca1 (out,a,b,op);
  
  initial
  begin
      #40 a=32'b1; b=32'b1; op = 2'b00;
  end
  endmodule
  </code></pre>
  <p>The code is successfully compiling, but the output is not being displayed.</p>
  <p><a href="https://i.stack.imgur.com/q3JuY.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/q3JuY.png" alt="The attached image is of the simulation." /></a></p>