How does converting infix to postfix help solve the problem?
What is a "C_link assignment statement"?
Have you tried looking through your course notes for ideas?
You'll have to give more specific details of the exact problem you're trying to solve. Remember, we're not on your course (so don't share the context in which your comments probably have a fairly obvious meaning) and we can't read your mind.
I already asked if you've made a start on the code. As you're approaching the exam then presumably you've already solved some programming problems, so you should be able to form the basic outline of the code. For instance, have you determined what input the program will take, how it processes that input and what output it gives, if only in outline form at this time?
Maybe it would be helpful if you posted the entire assignment description in full, rather than giving a potted form of what you think it might say.