Call by value
Pascal         C/C++
function f(c: char) :
integer; forward;
TRADITIONAL C:
int f();
ANSI C/C++:
int f(char c);
 OR
int f(char);
NOTE: Strictly speaking, no C dialect absolutely requires to
declare a function before it is used. If a call to a previously
undeclared function is seen, the compiler assumes it is a
function returning int and, in the case of ANSI C/C++, makes
assumptions about the types of the actual parameters
appearing in the call. This serves as an implicit function
declaration.