Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the Foundation. It also allows you to define and call macros. A reverse-polish calculator stores numbers on a stack. Entering a number pushes it on the stack.
Arithmetic operations pop arguments off the stack and push the results.
To enter a number in DC, type the digits, with an optional decimal point. Exponential notation is not supported. To enter two numbers in succession, separate them with spaces or newlines. These have no meaning as commands. Print a usage message summarizing the command-line options, then exit.