clrscr is usually given after declaration of variables. why ?

[rocky2008]

clrscr() is usually given after the declaration of all variables. If it is given before the declaration(of variables), the compiler points out an error. Why is this due to ? Will there be any problem in allocating the required amount of memory if at all clrscr() is given before the declaration?

Kindly reply to this question !!

Thanks !!

[__avd]

Read "C Program Structure" section from your text book. I am sure, you will get the answer.

[Ancient Dragon]

you can't put executable statements before variable declarations in C language.

[rocky2008]

i couldn't find the answer. can u please help me if you know the answer.
Read "C Program Structure" section from your text book. I am sure, you will get the answer.

[rocky2008]

thanks for your response. but can u please tell me why executable statements cant be given before variable declaration ?
you can't put executable statements before variable declarations in C language.

[Ancient Dragon]

If the answer is not in your text book then you need a different book! But I'm sure its in the book, you just need to study the sections about C language program structure.

// includes go here
#include <stdio.h>
...
int main(int argc, char* argv[])
{
    // all variable declarations go here
    //
    // executable statements follow
    //
    {
         // new block, so more variables here
         // followed by executable statements
    } // end of block
} // end of main() function

[Ancient Dragon]

thanks for your response. but can u please tell me why executable statements cant be given before variable declaration ?

Yes -- because the iso standards say so. I have read that this requirement is going to be relaxed in the next revision of the standards, but no compilers have implemented that yet (for obvious reasons)

[rocky2008]

oh!! then does this problem arise because of the problem in allocating the required amount of memory by the compiler ?

Yes -- because the iso standards say so. I have read that this requirement is going to be relaxed in the next revision of the standards, but no compilers have implemented that yet (for obvious reasons)

[Ancient Dragon]

oh!! then does this problem arise because of the problem in allocating the required amount of memory by the compiler ?

Its not aproblem. The C language was designed like that some 35+ years ago (officially 1972).

[rocky2008]

hmmm... ok... thanks !!
Its not a problem. The C language was designed like that some 35+ years ago (officially 1972).

[__avd]

Here is the structure of c program:

C Program has three sections:

--------------------------Section 1--------------------
General declaration & File inclusion section
Note: In this section you may put header files and
declaration : variables, struct, user defined function etc.

------------------------Section 2------------------------
Entry Point main() function definition
Note: Further, every c function definition is falls into two sub-sections.
int main()
{
----------- Local declaration -------------
variables, struct, user defined function etc....

------------Statements-------------------
..
return 0;
}

--------------------Section 3 ----------------------
User defined function definition.

Lets look at this code:

/* general declaration & file inclusion */
#include <stdio.h>

void test(int n);  

/* Entry point - main() function */
int main()
 {
    /* declaration  & initilization*/
     int k=10;

    /* statements */
    test(k);

   return 0;
  }

void test(int n)
 {
     /* declaration */
      int p;
    
     /* statements */
     p=n*n;
     printf("\nSquare : %d",p);
}

[Narue]

>I have read that this requirement is going to be relaxed in the next
>revision of the standards, but no compilers have implemented that >yet (for obvious reasons)
Mixing declarations and executable statements is a feature that's been available since C99, and quite a few compilers support it.