function calling

[help me]

can some 1 explain "call by refernce" and "call by value"?plz!

[Magos]

Here, a copy of the original variable is passed. Any changes made to it inside the function will not alter the variable passed to it.

void Function(int MyVariable)
{

}

Here, a reference to the variable is passed. Any changes made to it inside the function will also change the value of the variable you passed to it.

void Function(int& MyReference)
{

}

Here, a pointer to the variable is passed. It is basically the same as a reference, but pointers can change what they point at at runtime plus they have a kind of tri-state, a NULL pointer, which doesn't point at anything valid. A reference always points at something.

void Function(int* MyPointer)
{

}

[Cshot]

And here's an example:

#include <stdio.h>

void CallByValue(int val)
{
   val *= 2;
}

void CallByRef(int *pVal)
{
   *pVal *= 2;
}

int main()
{
   int value = 5;

   CallByValue(value);
   printf("Call By Value, value = %d\n\n", value);

   CallByRef(&value);
   printf("Call By Reference, value = %d\n\n", value);

   return 0;
}

[Hammer]

>>void Function(int& MyReference)
You forgot to mention this is for C++ only

[Magos]

Originally posted by Hammer
>>void Function(int& MyReference)
You forgot to mention this is for C++ only

This is the C-board? Dang, missed that. LOL!