#define clrscr() 100
main()
{
clrscr();
printf("%d\n",clrscr());
}


Answer:
100


Explanation:
Preprocessor executes as a seperate pass before the execution of the compiler. So textual replacement of clrscr() to 100 occurs.The input program to compiler looks like this :
main()
{
100;
printf("%d\n",100);
}

Note:
100; is an executable statement but with no action. So it doesn't give any problem