Thread: Type of function

I understand four type of function in c language as following

Code:

void foo (void) // Functin does't take any value and doesn't return any value 
void foo (int X) // Functin take value store in X and doesn't return any value 
int foo (void) // Functin does't take any value and return integer value
int foo (int X) // Functin take value store in X and return integer value

I don't understand following type of function

Does it valid function?

Code:

int *foo ( int X)

What type of function it is ? What does it return ?

Originally Posted by laserlight

It's the same as your last example, except that the return type is pointer to int.

Thank you

Code:

struct S *F (struct S *T){
	return T;
}

S is structure Name, T is structure variable

Is this function pass pointer to structure type struct ?
Is this function return pointer to structure type struct ?

What is F ? Is the function name F?

Originally Posted by laserlight

I can of course tell you the answer right now, but this kind of exploration will help you get a stronger grounding in the concepts and syntax than just a quick reply from a community member.

I have written following code Just for doing experiment I have explain all with comments

Code:

#include<stdio.h>

// function F get content of Y pointer and return pointer P to function
int *F (int *P)
{
  printf("P = %p \n", P); // Print content of pointer Y
  ++P;  // increment pointer value 
  return P; // return pointer P
}
int main ()
{
	int *Y;  // Decleare pointer to integer 
	printf("Y = %p\n", Y); // Print content of pointer Y
    Y = F (Y);	// call function F and pass content of Y
	printf("Y = %p\n", Y); //  print content of Y after calling function 
	return 0;
}

Y = 00400080
P = 00400080
Y = 00400084