Function prototype: Difference between revisions

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Function prototypes are typically included in a header file at the beginning of a source file prior to functional code. However, this is not enforced by a compiler.

<lang c>int noargs(); /* Declare a function with no ~~arguments~~ that returns an integer */

<lang c>int noargs(void); /* Declare a function with no argument that returns an integer */

int twoargs(int a,int b); /* Declare a function with no arguments that returns an integer */

int twoargs(int a,int b); /* Declare a function with two arguments that returns an integer */

int twoargs(int ,int); /* Parameter names are optional in a prototype definition */

int anyargs(~~...~~); /* An ~~ellipsis~~ can be used to declare a function that accepts varargs */

int anyargs(); /* An empty parameter list can be used to declare a function that accepts varargs */

int atleastoneargs(int, ...); /* One mandatory integer argument followed by varargs */</lang>

=={{header|C++}}==

Function declaration in C++ differs from that in C in some aspect.

<lang cpp>int noargs(); // Declare a function with no arguments that returns an integer

int twoargs(int a,int b); // Declare a function with two arguments that returns an integer

int twoargs(int ,int); // Parameter names are optional in a prototype definition

int anyargs(...); // An ellipsis is used to declare a function that accepts varargs

int atleastoneargs(int, ...); // One mandatory integer argument followed by varargs

template<typename T> T declval(T); //A function template

template<typename ...T> tuple<T...> make_tuple(T...); //Function template using parameter pack (since c++11)

</lang>

=={{header|COBOL}}==