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C program to shut down or turn off computer

C program to shut down your computer: This program turns off, i.e., shut down your 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 programming code for Windows 7

#include <stdio.h>
#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 shutdown immediately you can write "shutdown /s /t 0". If you wish to restart your computer, then you can use "shutdown /r."

C programming code 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".

If you are using Turbo C Compiler then execute your program from command prompt or by opening the executable file from the folder. Press F9 to build your executable file from source program. When you run program from within the compiler by pressing Ctrl+F9 it may not work.

C programming code 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 help or options type "man shutdown" at your terminal.