Confused !!!

[Unregistered]

i am totally confused.
It is writen in books that memory is alocated in case of definition and not declaration.
but when we write
int i;//declaration
still the memory is allocated..pls guide me
Also in character arays the terminating character is '\0'(NULL).then what is the terminating character in integer arrays ?????

[s_ruchit]

first your second question,

in any kind or type of array remember that the terminating char. is always NULL which is '\0'..
here's the proof for that..
try this program for that..

void main()
{
int a[] = {1,2,3,4,5,6,7};
int i;

for(i=0;a[i]!='\0';i++)
printf("%d",a[i]);

getch();
}


now your first question.
one thing you must know is that memory is always there,but you are only allowed to access your memory by reserving with variables.

here declaration and defination is tottaly different.

see i have 128 MB of memory.

but when i write " int i " i am having 2 bytes reserved for me from the total memory.

here's your the sentense

"memory is alocated in case of definition and not declaration. "


means that you are telling the compiler that what kind of data you are going to store in the memory.


if int then 2 bytes
if char then 1 byte
if float then 4 byte
if long float then 10 bytes..

etc..

[Monster]

Originally posted by s_ruchit
first your second question,

in any kind or type of array remember that the terminating char. is always NULL which is '\0'..
here's the proof for that..
try this program for that..

void main()
{
int a[] = {1,2,3,4,5,6,7};
int i;

for(i=0;a[i]!='\0';i++)
printf("%d",a[i]);

getch();
}

Kids..... don't try this at home.

The null character is only used for character arrays and not for integer arrays.
Therefore the above example will not work.
The null character is in fact the same as the number 0, so you can't use the null character to terminate an integer array.

B.t.w.

void main is wrong, use int main
the size of int depends on the OS you are using (4 bytes for win32)

[dv007]

Monster is almost rite!
I want to add some more..
Base on my experience with C

int Arr[] = {1,2,3,4,5,6,7};
In this scenerio, TERMINATE Value is garbage.(chunk)

int Array[8]= {1,2,3,4,5,6,7};
In this scenerio, if you try to create an extra
cell, Array[7] without initialize a value to it, then it automaticly put a ZERO (0) to it.
Unfortunately, C compiler don't check the boundary of array. This is a weakness in C and also not
strong type checking programming language.
Look, you can do this in C:
int A[]= {1,2,3};
int i;
for (i= 0; i< 10; ++i) /* i suppose to be less than 3 (i <3)
printf("%d\n", A[i]);

Interesting huh??

DV009

[Monster]

Originally posted by dv007
Monster is almost rite!
I want to add some more..

Then what part is wrong!

[Salem]

> int i;//declaration
> still the memory is allocated..pls guide me
If all you provide is
int i;

The compiler/linker will create
int i = 0;
for you, and it's this which creates the definition, and causes space to be allocated.

If you have Kernighan and Richie "The C Programming Language 2nd Ed" to hand, then A10.2 explains.