c program to check the alphabet is in uppercase or in lowercase

#include<stdio.h>
#include<conio.h>
void main()
{
 char a;
 clrscr();
 printf("enter an alphabet:");
 scanf("%c",&a);
 if(a>='A'&&a<='Z')
 printf("upperchase");
 else
 printf("lowerchase");
 getch();
 }