clrscr in C

clrscr function in C

clrscr stands for:

clr = clear

scr= screen

When the clrscr() function is called in a program everything currently displayed in the console(output of previous programs, output of current program, user inputs, error messages etc) screen is cleared or deleted.

Basically the clrscr(); function clears the terminal (console) window in which you are currently working and places the cursor (pointer) to the top left position of the window.

It is a predefined function in "conio.h" (console input output header file) used to clear the console screen.

*The use of the clrscr() function in C is always optional but it should be placed after variable or function declaration only.

Why use the clrscr function in C?

If you go on running the program several times, the output of the program gets longer for each execution, as the output of the previous program remains on the console window, which makes it cumbersome.

This can be avoided using the clrscr() function.The clrscr() function must be used in the program main() body. It is always used after the variable declaration instructions.

What it does is, everytime we execute our program, only the output of the current execution will be visible on the terminal window. All the previous outputs which were displayed earlier will be cleared.

clrscr() function simply clears all existing content on the console. You can understand the difference in a much better way by just running your code, once using clrscr() and once without clrscr().

Program: clrscr in C

#include<stdio.h>
#include<conio.h>
void main()
{
int x = 5, y = 15;
int sum = 0;
clrscr();           // using clrscr() after variable declaration
sum = x+y;
printf("Sum is equals to: %d",sum);
getch();


}

Output :

Sum is equals to: 20

Note:

clrscr() is a function used by Borland Turbo C, which is an old IDE(Integrated Development Environment) in MS DOS and Windows platform. Due to old habits and persistent use of common textbooks in our curriculum, the use of this obsolete compiler and IDE  still exists, especially among many Indian and South Asian developers communities.

Hence, many new compilers may throw errors while implementing this function. It is better to use any IDE that supports clang or GCC.

* People may face errors like undefined reference to `clrscr'

which is bound to happen to some compilers because new compilers may not consist of the implementation of this function.

Summing up:

There are several methods to clear the console or output screen and one of them is the clrscr() function.

It clears the screen(terminal) as function invokes. It is declared in the “conio.h” header file and must be implemented in the main() body. The use of the clrscr() function is optional but should be placed after variable or function declaration only.

There are some other methods too like system(“cls”) and system(“clear”) and these are declared in the “stdlib.h” header file. They are also used to clear the console.

Here is the syntax to clear the console in C language,

clrscr();    //clrscr function


OR


system(“cls”);  


OR


system(“clear”);
x