The Stack

Manipulating the Stack

The basic idea of an RPN calculator is that you have a stack of numbers that you perform operations on. To place a number on the stack simply type the number in the input field and hit enter. This places the number on the stack and allows you to perform operations on it or place more numbers under it.

Try this example. Hit
5
$<$ENTER$>$
3
$<$ENTER$>$
+
$<$ENTER$>$

This places 5 on the stack. Then 3 below it, then adds the two numbers. You should now only have the number 8 on the stack. Remember that you need 2 numbers on the stack to perform a binary operation like addition or multiplication.

You can perform unary operations with this calculator. With the 8 on the stack you can press the sqrt key and you will see 2.828427 (the approximation of the square root of 8). Most of the keys are pretty self explanatory.

you can also input numbers onto the stack in infix notation. try to input: $1/sqrt(2)$
$<$ENTER$>$

gcalcrpn will evaluate the input string and place it's value on the stack, where you can manipulate it further with regular rpn operations. This infix input will work with any entry field in the calculator.