ABC - desk calculator with algebraic expression evaluation. ABC also features a summation operator and a library of mathematical functions. ABC prompts the user for input by typing six spaces and then waiting for input. ABC will print the results of the expression evaluation immediately and will then prompt the user for more input. Parentheses may be used in the standard way to group operations together.
All trig functions require X to be in radians.
The names of the functions are reserved words, and must not be used as variables. A FOR variable is used to supply a range of values to an expression. Up to three variables may be given a range of values for the summation by means of FOR statements. Such an expression may be entered by continuing it on the next line. ABC will print another question mark and the remainder of the line may then be entered.