error handling and solution

i'm a student and i need some help in doing my assignment. currently my problem is that i need to code on error handling. i'm doing it in a web based form. when the user enter a programming code such as c++ into the compiler, the compiler then process and return the result. if the code contains error, the program could show the solution and guide the user step-by step solution. if the program is error free, then it could be compiled straight away and return the result in the html or php language. i don't know how to do the coding and i really need help.