What is “Clean C” and how does it differ from standard C? [closed]

Answer 1

Clean C is a term coined in Harbison & Steele book (C: A Reference Manual, Prentice Hall). A program is said to be written in Clean C if it can be compiled by a Standard C compiler and a Standard C++ compiler; and its execution would not produce different observable behavior from the two compilers (the issues of optimizations being irrelevant).

Answer 2

One that strikes me as being the most obvious is that in C++, you have to cast the return value of malloc. Also structs are automatically typedefed in C++.

Always use a C compiler for C code, not C++. C++ isn't perfectly compatible with C.

A few others differences may be:

• In C, declaring void func(); declares a function that hasn't specifed what its arguments are, whereas in C++, void func(); is equivalent to the C void func(void)', taking no arguments;
• Prototypes are required in C++, whereas it's generally just a warning in C;
• The type of character constants (like 'a') is int in C and char in C++;
• The type of string literals is char [] in C and const char [] in C++;
• Some legitimate variable names in C, like class, are reserved keywords in C++.