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Convert infix to postfix and evaluate postfix expression.

For example: 4 // number of variables
g = 2
p = 3
t = 1
w = 2

3 // number of equations
g + p x t - w x p
t - g + t - w
e + t x t - m

Output: -1 //for first equation
-2 //for second equation
Compilation Error // for third equation

Convert infix to postfix and evaluate postfix expression.

For example: Input:
3 // number of variables
a = 1
b = 2
c = 2

2 // number of equations
a x b + a x c + b x c
a x c - b / c + c x c

Output: 8 //for first equation
5 // for second equation

How to evaluate a mathematical expression by compiler design. The program will ask the user to input a value (say n). Then user will input n lines of input each of which contains an identifier and its corresponding value. Then program will ask the user again to input a value (say m). Then user will input m lines of expressions. Calculate the final value for each of the given expression using first n lines of input. If you can't evaluate any expression from given numbers of identifiers then output 'Compilation Error'. Allowed mathematical operators are +(add), -(subtract), x(multiply), /(divide).

Example: a = 1
b = 2
c = 2


a x b + a x c + b x c output 8
a x c - b / c + c x c out put 5


g = 2
p = 3
t = 1
w = 2

g + p x t - w x p output -1
t - g + t - w output -2
e + t x t - m output compilation error