How to clear screen from simple C program?

Question

#include <stdio.h>
#include <cstdlib>

rec();

main() 
{
    int a, fact;
    char q, n, y;
    printf("\nEnter any number ");
    scanf("%d", & a);
    fact = rec(a);
    printf("Factorial value = %d\n", fact);
    printf("do you want to exit.....(y/n):");
    scanf("%s" ,&q);
    if (q == 'n')
    {
        system("cls");
        main();
    }
    else
        return 0;
}

rec(int x) 
{
    int f;
    if (x == 1) 
        return 1;
    else 
        f = x * rec(x - 1);

    return f;
}

I'm using code blocks but I don't know how to clear the screen. I searched then found system("cls"); within header file #include<cstdlib>, but it shows the error cstdlib: no such file of directory. What should I do ?

When in doubt, please do visit these links, to know, which function belongs to which header file or which header file has which function :-) [Alphabetical Index](http://pubs.opengroup.org/onlinepubs/009695399/idx/index.html) and [Headers Index](http://pubs.opengroup.org/onlinepubs/009695399/idx/headers.html) — nIcE cOw, Feb 27 '13 at 02:59
`main()` -> `int main(void)` and `rec();` -> `int rec(int x);` — MD XF, Mar 05 '17 at 05:31

score 9 · Answer 1 · answered Feb 27 '13 at 02:13

9

Change

#include <cstdlib>

to

#include <stdlib.h>

cstdlib is a C++ header file, and thus will be unusable in C.

answered Feb 27 '13 at 02:13

Karthik T

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just a flash of another screen comes n went off. but the curren screen remains as it is without clearing screen – Rahul Subedi Feb 27 '13 at 02:42
@RahulSubedi That is an unrelated problem really.. Looks like `system` is opening a new terminal instead of using the current one. Have you tried running the program from the command line instead of from eclipse? – Karthik T Feb 27 '13 at 02:47
@RahulSubedi luser droog has some insights about your clearing the screen problem – Karthik T Feb 28 '13 at 06:15
I have tried this but I am getting the error: `sh: cls: command not found` – maxisme Oct 21 '14 at 21:39
@Maximilian try `clear` instead. That needs to be a func supported by your shell – Karthik T Oct 22 '14 at 04:16

luser droog · Accepted Answer · 2014-11-17T06:34:49.250

Clearing the screen is outside the purview of a normal C program. It depends on the operating system.

For windows, you should look into conio.

For unix, look into curses or termios.

system() always launches a sub-shell which may or may not have any effect on the environment of the parent program. You do need a system-call, but not a system() call.

I didn't always know this. I once (long ago) suggested in comp.lang.c that someone should try system("exit"); to close the window around the DOS program. But that, of course, cannot work. And I was quickly advised to test my code before posting. :)

score 4 · Answer 3 · answered Feb 27 '13 at 02:13

4

you have lots of problems in your code....

but for the specific problem, try #include <stdlib.h>

answered Feb 27 '13 at 02:13

Keith Nicholas

43,549
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#include also didnt worked. just a flash of another window come n goes away n the current window remains same without clearing screen – Rahul Subedi Feb 27 '13 at 02:28

score -1 · Answer 4 · answered May 23 '16 at 23:22

-1

use the #include<stdlib.h> that's where the clear screen function is defined.

answered May 23 '16 at 23:22

jackotonye

3,537
23
31

score -1 · Answer 5 · edited Nov 01 '16 at 18:28

-1

To use system("cls") you need the header <iostream>. This will allow all system() types to execute. Unsure if it is a C++ header file, but it works for the compiler that I use.

edited Nov 01 '16 at 18:28

Paul Roub

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answered Nov 01 '16 at 18:27

Mike

1

How to clear screen from simple C program?

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