C program to shut down or turn off the computer
C program to shut down your computer, i.e., to turn off a computer system. System function of “stdlib.h” is used to run an executable file “shutdown.exe” which is present in C:\WINDOWS\system32 folder in Windows 7 & XP. See Windows XP and Linux programs at the bottom of this page.
C program for Windows 7
#include <stdlib.h>
int main()
{
system(“C:\\WINDOWS\\System32\\shutdown /s”);
return 0;
}
You can use various options while executing “shutdown.exe,” for example, you can use /t option to specify the number of seconds after which shutdown occurs.
Syntax: “shutdown /s /t x”; where x is the number of seconds after which shutdown will occur.
By default, shutdown occurs after 30 seconds. To shut down immediately you can write “shutdown /s /t 0”. If you wish to restart your computer, then you can use “shutdown /r.”
C program for Windows XP
It will ask if you want to shutdown your computer, if you press ‘y’ then your computer will shutdown in 30 seconds.
#include <stdio.h>
#include <stdlib.h>
int main()
{
char ch;
printf(“Do you want to shutdown your computer now (y/n)\n“);
scanf(“%c”, &ch);
if (ch == ‘y’ || ch == ‘Y’)
system(“C:\\WINDOWS\\System32\\shutdown -s”);
return 0;
}
To shutdown immediately use “C:\\WINDOWS\\System32\\shutdown -s -t 0”. To restart use “-r” instead of “-s”.
C program for Ubuntu Linux
#include <stdio.h>
int main() {
system(“shutdown -P now”);
return 0;
}
You need to be logged in as root user for this program to execute otherwise you will get the message shutdown: Need to be root, now specifies that you want to shut down immediately. ‘-P’ option specifies you want to power off your machine. You can specify minutes as:
shutdown -P “number of minutes.”
For more options or help type “man shutdown” in a terminal.