Assignment vs. Initialization

I'm studying for an exam and just came across a sentence: "Initialization isn't the same as assignment." What? I thought when you assigned a variable a value, you're initializing the variable. If not, could someone clarify assignment vs initialization?

Thanks!

There is defference between defination and declaration its same as initaililization and assignment, when u initialize a variable it means u r making identify the variable to your compiler, but when you assign you get the adress assigned for that variable for your compiler.
e.g. Intialization

Code:

---

int i;

---

assignment

Code:

---

int i=0;

---

or in OOPS

Initialization

Code:

---

Object obj;

---

Assignment:

Code:

---

Object obj = new Object( arg list );

---

This is not true.
This is also the C board, no such things as classes which is a C++ term.

Code:

---

int i;

---

No initialization.

Code:

---

int i = 0;

---

Initialization to 0.

Code:

---

int i; */ Initialization */
i = 0; /* Assignment */

---

I don't think initialization vs assignment has such a big impact in C. More so in C++.

Yes, and there are several cases where the difference is noticeable, particularly when it comes to structures and arrays.

You can initialize an array or struct with constant values, e.g. :

Code:

---

struct blah
{
  int x;
  char *s;
};

struct blah array[3] = { { 1, "One"}, {2, "Two"}, { 3, "Three" } };

// However, this doesn't work:
struct blah array[3];

array = { { 1, "One"}, {2, "Two"}, { 3, "Three" } };

// Also won't work:
struct blah array[3];
struct blah arr2[3];
...
array = arr2;

// This works, however
array[1] = arr2[1];

---

That covers both structure and array initialization. Essentially, the compiler is able to give a variable a value when it's defined, but not later - you can only assign one element at a time from an array for example, and you can not assign constant values directly to a struct as a list of element values, each element on it's own will have to be set.

--
Mats

The problem with using syntax alone to define the term is that:

Code:

---

int i;

---

would not be initialized and thus have an indeterminate value if i has automatic storage duration, but would be initialized to 0 if i has static storage duration.

Perhaps we should just state:
Initialization means providing an initial value to an object (where object means "a contiguous region of memory holding a value of some type"). Assignment means providing a new value to an object that has been initialized or that has an indeterminate value.

Oooh. So initialization is basically creating a variable and assigning it a value all in go, and assignment is changing the value of an already existing variable. It makes more sense when you say it like that.

Yes. Or creating a variable with a value (initialization).
I think laserlight's definition of initialization is a good one.