What is function prototype?

Answer 1

In C++ all functions must be declared before they
are used. This is accomplished using function
prototype. Prototypes enable complier to provide
stronger type checking. When prototype is used,
the compiler can find and report any illegal type
conversions between the type of arguments used
to call a function and the type definition of its
parameters. It can also find the difference
between the no of arguments used to call a
function and the number of parameters in the
function. Thus function prototypes help us trap
bugs before they occur. In addition, they help
verify that your program is working correctly by
not allowing functions to be called with
mismatched arguments.

Answer 2

function prototype is a statement which is used to notify the compiler of a function , it's return type, and the parameters before they defined usually later in the program after the main function.
it can be easily spotted as a function but with a (;)at the end after the closing bracket

Answer 3

A prototype simply means a function declaration above main ().

if you define your main function at the top of your program then define other functions after the main function, you need to add your prototypes above main to make the function call in main understand that your prototype has a declaration somewhere in your source file.

void buyFood (int); - Prototype
void typeOfFood (string); - Prototype

int main ()
{
typeOfFood ("rice");
buyFood (10);

getchar ();
return 0;
}

void buyFood (int amount)
{
cout << "my food costs " << amount << " usd" << endl;
}

void typeOfFood (string food)
{
cout << "i am eating "<< food << endl;
}

Answer 4

a function prototype or function interface is a declaration of a function that specifies the function's name and type but omits the function body.
e.g.

int add (int a, int b);