Flex Bison Calculator

• Supports the following math functions :
           Add - Subtract - Divide - Multiply - Power - Assignment - Sin - Cos - Sqrt - Abs - Exp - Sinh - Cosh
• Can recognize both Integer and Float values.
• Can recognize scientific values as Float (e.g. 314e-2 = 3.14).
• Can Assign values to identifires using "=" sign.
• Prints out a list of used Tokens in each command.
• Prints out the final output of the enterd math function as a Double value.

CFG

The equivalent CFG for the grammer used in this project is as follows :

stmts → stmt stmts
stmts → ε
stmt → 𝑖𝑑 {𝐸𝑚𝑖𝑡(lvalue + 𝑖𝑑. 𝑙𝑒𝑥)} = expr{𝐸𝑚𝑖𝑡("𝑎𝑠𝑠𝑖𝑔𝑛")};
expr → expr + term {𝐸𝑚𝑖𝑡("𝑎𝑑𝑑")}
expr → expr − term {𝐸𝑚𝑖𝑡("𝑠𝑢𝑏")}
expr → term
term → term ∗ unary {𝐸𝑚𝑖𝑡("𝑚𝑢𝑙")}
term → term / unary {𝐸𝑚𝑖𝑡("𝑑𝑖𝑣")}
term → unary
unary → −unary {𝐸𝑚𝑖𝑡("𝑛𝑒𝑔")}
unary → pow
pow → factor ^ pow {𝐸𝑚𝑖𝑡("𝑝𝑜𝑤")}
pow → factor
factor → id {𝐸𝑚𝑖𝑡("rvalue " + 𝑖d. 𝑙𝑒𝑥)}
factor → 𝑖𝑛𝑡 {𝐸𝑚𝑖𝑡("𝑝𝑢𝑠h " + 𝑖𝑛𝑡. 𝑙𝑒𝑥)}
factor → 𝑓𝑙𝑜𝑎𝑡 {𝐸𝑚𝑖𝑡("𝑝𝑢𝑠h " + 𝑓𝑙𝑜𝑎𝑡. 𝑙𝑒𝑥)}
factor → (expr)
factor → sin(expr) {𝐸𝑚𝑖𝑡("𝑠𝑖𝑛 " )}
factor → cos(expr){𝐸𝑚𝑖𝑡("𝑐𝑜𝑠 " )}
factor → sqrt(expr){𝐸𝑚𝑖𝑡("𝑠𝑞𝑟𝑡 " )}
factor → abs(expr){𝐸𝑚𝑖𝑡("𝑎𝑏𝑠 " )}
factor → exp(expr){𝐸𝑚𝑖𝑡("𝑒𝑥𝑝 " )}
factor → sinh(expr){𝐸𝑚𝑖𝑡("𝑠𝑖𝑛h " )}
factor → cosh(expr){𝐸𝑚𝑖𝑡("𝑐𝑜𝑠h ")}

Usage

First of all, please make sure that both Flex and Bison are installed.
To use the calculator, clone the project. Open command prompt and cd to the directory. Then use the following commands. If there were warnings, ignore them.

bison -d -y calc.y
flex calc.lex
gcc -c y.tab.h y.tab.c lex.yy.c
gcc y.tab.o lex.yy.o -o $@ -lm

A Unix executable file named "-lm" will be generated. open the file and enjoy!

Example

a=2
T_IDEN  T_EQL  T_INT  = 2.000000
a^3
T_IDEN  T_POW  T_INT  = 8.000000

23 + sin(sqrt(16))
T_INT  T_ADD  T_SIN  T_PRNL  T_SQRT  T_PRNL  T_INT  T_PRNR  T_PRNR  = 22.243198

100 + 2e2
T_INT  T_ADD  T_FLOAT  = 300.000000