I'm working on a little program to read mathematical expressions, solve the equations and print out the answers.

The problem is that it has to support variables.

Example:

a+2 = 3

and in the future, while running the program, I may use the value of 'a' ,that's supposed to be calculated by the program from the expression above, to find the value of yet another variable ('b').

Example:

a+b = 5

I've started to implement the program, but I can't figure out how to dynamically create identifiers with the names of the variables from the equations.

Does anyone know how I can do this?