error as unknown preprocessor directive:warning

//PreProcessor Conditional Compilation
#include<stdio.h>
#include<conio.h>
#define Num 85
int main(void)
{
	clrscr();
	#ifdef Num
		printf("Num is Defined to %d",Num);
	#endif
	#ifndef Number
		#warning Number is not defined
		printf("\nNumber is Not Defined");
	#else
		#error Preprocessor NEVER reaches here
		printf("\nNumber is Defined to %d",Number);
	#endif
	getch();
	return 0;
}