convert int to const int

I wrote like this but it isn't work

Code:

(const *)example;

example is int. how can I do this??

shoud be just

Code:

(const int) example;

since its your not coverting into const integer pointer.

ssharish

Const is not a type. You can only cast to a new type. A type can be constant, however, so applying const to the type will make it constant.

it isnt work! I have simple struct and I want to use like this

Code:

void example(int *vle)
{
      .....
      struct exam{
             ......
       }x[(const)*vle]

}

but "x[bla]" you now bla must be const int so I get error..
sory my english.

Const is not a type.
Use (const int).

I used it (const int) but result didnt change...

I get this error
1)Constant expression required
2)Constant variable 'x' must be initialized

I suppose you are trying to create an array of structs with a non-constant expression. This is illegal.
Consider:

Code:

int n = 10;
int myarray[n]; /* Illegal */
int myarray[10]; /* Legal */

It is allowed to create a dynamic array on the stack in C99, but not C89.

But I must get struct size from another result.. Cant we do this?? :S

It's possible via dynamic memory.
That is malloc and free. Malloc to allocate a dynamic size of memory and free to free it later when you don't need it.

Originally Posted by koyboy

But I must get struct size from another result.. Cant we do this?? :S

Yes you could dynamically allocate it use it malloc!!! Given the size and the struct type. You need to be familiar with pointers!

ssharish.

thanks for advice but I didnt it in struct.. if I use int so I can do like this:

Code:

int * number = (int *) malloc(*nos);

is it true?? I think yes but I never do it for struct.. How can we do this??

Originally Posted by koyboy

thanks for advice but I didnt it in struct.. if I use int so I can do like this:

Code:

int * number = (int *) malloc(*nos);

is it true?? I think yes but I never do it for struct.. How can we do this??

Should be

Code:

int * number = (int *) malloc( *nos * sizeof(int) );
 
and check for error
 
if( number == NULL )
   report error;

You need to specifgy the size to the malloc, otherwise the malloc will assume one byte for every element, which in your case should be int. Since you are trying to allocate integer vector. In the same way if you are allocating float then just replace sizeof(int) with sizof(float) and same applies for the other datatypes.

ssharish

Yes :S but I want it for struct like this

Code:

void example(int *vle)
{
      .....
      struct exam{
             ......
       }x

}

I want to use malloc for x struct??
and add one more question how can we do this for char array??

Code:

void example(int *vle)
{
      .....
      struct exam{
             int in;
             float flo;
      };
      
      struct exam *container = malloc( sizeof( struct exam ) * *vle );
      
      // Check for return value of malloc and report error on failure.
}

ssharish

Another, more popular way:

Code:

struct exam* container = malloc(sizeof(*container) * *vle);

And never cast the return of malloc.