C Functions

In C, we must declare a function prototype before calling the function so that the signature is known to the compiler

• this is no different from declaring an int with int e
• The prototype looks identical to the function, expect the body is replaced by a semi-colon:

char *do_something(char *dest, const char *src);

This is not strictly necessary, but unless we declare it, the compiler is left to guess the signature based on how the function is called, and it is often wrong.

• if we are passing an argument that should remain constant within the function body, we can prepend const to the parameter: int strlen(const char[]);