CSC322 C Programming and UNIX - Department of Computer ...

Basic idea:
Implementation
– Input is a sequence of numbers and operators
– If a number is read, it is pushed onto a stack
– If an operator is read, the necessary number or arguments is popped of the
stack, the operation is performed, and the result is placed in the stack
Input and output can happen in any representation from base 2-16
– There is a strong convention for representing these numbers:
∗ Digits are 0-9 with nominal value, A-F (or a-f) with values 10-15
– Input and output use independent bases (base conversion made easy)
Recognizing numbers and operators
– Any string of valid digits in the current input base is a number
– Any string starting with - and directly followed by valid digits in the current
input base is a number
– Everything else is treated as an operator
Stephan Schulz 188