function prototypes question.

[InvariantLoop]

what good are function prototypes for? in the book that in reading they have an example where the code below appears on line 3

 
int Area(int Length, int Width); //function prototype

on line 27 the function appears as

int Area(int L, int W)
{
    return L * W;
}

so the protoype is not the same, so whats the purpose of having it there if it doesnt do anything?

im new so silly questions r a must!

[Salem]

Something between line 3 and line 27 could call Area()
WIthout a prototype, that would be an error.

Just look in any header file you include, those are all prototypes.

You can only write trivial programs which can be expressed
a) in a single file
b) with no mutual recursion
without the need to write a prototype.

[InvariantLoop]

still a bit confused but i think i understand what u mean, i have another question
what does this mean

void MakeArray(ArrayType NumArray, int & count)

im talking about the & sign between int and count

[Prelude]

>im talking about the & sign between int and count
It means that count is a reference to int. You can safely assume that any changes to count will have an effect on an integer from the calling function.

[elad]

in the prototype, the names of the variables are immaterial, in fact they aren't even necessary. The argruments in the pototype only needs to have the class type indicated. The class type need to be the same, in the same order in the prototype and the first line of the definition but the variable names can be different. The function body will use the names of the variables as listed in the first line of the function definition, irrespective of the name of variables in the prototype and irrespective of the names of the variables passed to the function in the function call.

//prototype
int add(int a, int b);
 
//function call
int first = 3;
int second = 1;
int sum = add(first, second)
 
//definition
int add(int lhs, int rhs)
{
   return lhs + rhs;
}