Algorithm 3: Modified chromosome evaluation procedure.

for Each gene in chromosome do

if The gene is an operator then

Pop 2 operands from stack

if Arity of the operator $<2$ then

Discard the 2nd operand

end if

Execute the operation

Push the result back on stack

else  //Comment: the gene is an operand

Push the operand on stack

end if

end for

The element left on the stack is the value of the evaluated expression.