C Programming - Functions - Discussion

K&R C is an old de facto standard for the C programming language. It was established when the C language creators, Kernighan and Ritchie, wrote the definitive book on the language.

ANSI C is another standard that was created when C got popular enough, to establish a real standard (created by an actual standards institute) and also to improve upon the language. You might also hear this standard referred to as C89, since it was published in 1989. Newer standards such as C99 and C11 also exist today, but they are all much more similar to each other (and to C89) than to the original K&R C.

One huge reason for this is a very important change in the way functions are declared. In K&R C, for instance, if you want to write a function that takes in two arguments, one of type int and one of type double, and returns nothing, you would write;


void foo(a, b)
int a;
double b;
{
// implementation
}
Meanwhile, in any standard C89 or later, you would write

void foo(int a, double b)
{
// implementation
}

This second style is known as the function prototype.

The first style is useful and maybe interesting to know if you are reading really old code, but you should never ever use it yourself. Your compiler will likely yell at you, and even if it doesn't, functions written in the old style are not subject to the same type-checking rules as the function prototype.

Ex: KR notation:
---------------------
void display(__);
main()
{
display();
}
void display()
{
}

ASCII notation:
-------------------
void display(__)
{
}
main()
{
display();

Pre-ANCI Notation:
------------------

1)Main(net, err)
int *net;
double *err;
{

}

Please explain about this notation.

When a memory is allocated in functions during the function call or function definition?

I didn't find any difference between KR and ANSI.

Explain pre-ANSI notation?

What is kernighan and ritchie notation?

I think Memory is allocated only during function definition.

How structures are initialize? Explain.

Can you please write an example for all the notation which is present in the option?