pointer is variable which holds the address of another variable ,another function and incomplete in C.
incomplete means ----------void *p;
it's a generic pionter ,we can not allocate memory by dynamically with this .
size of pointer is depending on the memory model.
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Newbie Member
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| 11Sep2007,11:50 | #11 |
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Go4Expert Member
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| 12Sep2007,12:46 | #12 |
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very appropriately describe the difference between pointer and reference. I find it very valuable
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Newbie Member
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| 23Nov2007,14:17 | #13 |
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In C#, the object of a Class
1. is a reference ? or 2. is a STACK to HEAP pointer ? the objects shouldn't go into the HEAP ?  if they are references of the class instances.
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Newbie Member
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| 23Nov2007,17:21 | #14 |
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Thank you good difference...
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Go4Expert Member
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| 10Dec2007,15:05 | #15 |
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pointer is not necessary to initialize the pointer at the time of declaration and reference to initialize the Reference at the time of declaration .Ok thank you.
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Go4Expert Member
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| 7Jan2008,19:08 | #16 |
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Quote:
Originally Posted by sreeja |
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Ambitious contributor
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| 9Jan2008,05:03 | #17 |
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Quote:
Originally Posted by DaWei an implementation and performance point of view. They are, in that sense, pure syntactic sugar. The only difference is that in some cases a reference can be optimized away. I'm not saying they are a bad thing, they're good for what they are designed for. It's just incorrect to suggest that they offer a performance advantage over pointers. If you still disagree, consider this C++ and its assembly code (from g++ using -S flag): Code:
#include <iostream>
using namespace std;
void f( int i, int& r, int* p ) {
++i;
++r;
++*p;
}
int main() {
int i = 0, r = 1, p = 2;
cout<< i <<' '<< r <<' '<< p <<endl;
f( i, r, &p );
cout<< i <<' '<< r <<' '<< p <<endl;
}
Code:
... __Z1fiRiPi: ## f's mangled name: Z1(arbitrary) f(our name) iR(int&) iP(int*) i(int) pushl %ebp movl %esp, %ebp incl 8(%ebp) ## inc value at stack offset 8 (i) movl 12(%ebp), %eax ## load pointer at stack offset 12 (r) incl (%eax) ## inc indirect (dereference) movl 16(%ebp), %eax ## same as for r (p) incl (%eax) popl %ebp ret ... movl $0, -4(%ebp) ## Load the variables with 0, 1, and 2. movl $1, -8(%ebp) ## Note their constant addresses (stack offsets). movl $2, -12(%ebp) ## i is -4, r is -8, p is -12 (relative to ebp) ... leal -12(%ebp), %eax ## push p's address pushl %eax leal -8(%ebp), %eax ## push r's address (same as for p) pushl %eax pushl -4(%ebp) ## push i (value) call __Z1fiRiPi ## call f ... |
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TechCake
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| 11Jan2008,10:17 | #18 |
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You all are correct.
One main Difference is that Extra memory is taken by Pointer( Size depends on machine architecture i.e. 32-bit machine will be 32 bit size of pointer) But in case of reference is Only Alias for that object. Some book written that reference is just like a constant pointer. But it's not correct. Just reference 's behabiour is like constant pointer. |
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TechCake
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| 11Jan2008,10:18 | #19 |
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One More use of it is to cleanup Code in place of pointer.......
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Go4Expert Member
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| 25Feb2008,15:11 | #20 |
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Quote:
Originally Posted by asadullah.ansari |