completed atof with proper handling of negative signed exponents
rpolcalc.c input from text
added modulus and unary negation to reverse polish calculator
added stack operations for duplicate, swap, print, and clear
added mathematical functions to rpolcalc via first letter of the name
added functionality for variables via = 'a'
added ungets for a whole string calling ungetch repeatedly
EOF seems handled fine to me
added one char buffer fragment and completed the alternate design of rpolcalc with getline instead of getch, ungetc