Write a c program to print the answer of a task which is given as a single string as a value?

for eg:- if we give 5+3 as an expression the output should be 8


that is sum of the given expression


not by reading each character into one variable.


the input should be into one single string

Write a c program to print the answer of a task which is given as a single string as a value?
Here are some links:


http://finance-old.bi.no/~bernt/gcc_prog


http://howstuffworks.com/c.htm


http://www.cs.cf.ac.uk/Dave/C/CE.html