How to close windows using c program where user enters time
I have been studying c and I want to create a c program, all it has to do is shutdown the computer after a certain time of user input.
I know how to do an immediate close using this code:
#include<stdlib.h>
int main()
{
system("C:\\WINDOWS\\System32\\shutdown /s /t 00");
return 0;
}
I create an .exe file and execute it, it works fine. but I don't know how to shutdown after a while when the user logs in. I tried the # operator like:
#include<stdio.h>
#include<stdlib.h>
#define shutown(x) system("C:\\WINDOWS\\System32\\shutdown /s /t" #x);
int main()
{
int t;
printf("\n enter secs :");
scanf("%d",t);
shutdown(t);
}
but the program didn't work. I never used # operator, but did a search on it:
https://msdn.microsoft.com/en-us/library/7e3a913x.aspx
but I'm still not sure if I'm using the operator correctly.
I would also like to create a program that would create a folder in windows with a username, but I was planning on using the # operator and I think I am doing something wrong.
please tell me where i am going and any other logic to accomplish the same tasks.
Many thanks!
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An operator #
is a preprocessor operator, that is, everything is done at compile time. You cannot use values from the user there. What you actually get is:
system("C:\\WINDOWS\\System32\\shutdown /s /t" "t");
This is definitely not what you want.
You really want to have a local string buffer that you will print the value to using something like sprintf
and then callingsystem(buffer);
This will do what you want:
int main()
{
int t;
char buffer[100];
printf("\n enter secs :");
scanf("%d",&t); // Note that you need &t here
sprintf(buffer, "C:\\WINDOWS\\System32\\shutdown /s /t %d", t);
system(buffer);
}
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Your expression #define
shutdown
says shutown
(copy + paste error?).
To use a variable in a macro #define
, just enter the variable name. Example:
#define shutdown(x) system("C:\\WINDOWS\\System32\\shutdown /s /t" x);
but call any functions in the macro as if you were calling them elsewhere. It does not replace x
with a value t
, it replaces it with a literal t
. Hence,
system("C:\\WINDOWS\\System32\\shutdown /s /t" t);
will not work. You will need to concatenate the two lines with something like strcat
.
You will need #include <string.h>
to use strcat
, but after you did that changed shutdown
:
#define shutdown(x) system(strcat("C:\\WINDOWS\\System32\\shutdown /s /t ", x));
DISCLAIMER: I have not tested any of these codes, this is just a general guide. There might be problems, but that's the gist of what will work. Think of this as psuedocode.
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