I get an illegal operation error whenever I try to run this program:

Code:
#include <iostream.h>
#include <windows.h>


int main()
{
	
	LPSYSTEMTIME lp_time;
	float sec;

	sec=NULL;lp_time=NULL;	

	while (1==1)
	{
	
		GetSystemTime(lp_time);

     	sec=lp_time->wSecond; //This line probably causes the error
		
		cout<<sec;
	}

	return 0;
}
I think line 18 causes the error, becuase wenever I remove it and I ask it to cout the lp_time variable I don't get an error. Any ideas?