ASCII means American Standard Code for Information Interchange(a character encoding scheme means uppercase letters(A-Z), lowercase letters(a-z), special symbols($,&,#,@).
It control characters to the numbers ranging from 0-225.
#include<iostream.h>
#include<conio.h>
int main()
{
char cha;
clrscr();
cout<<"Enter any character";
cin>>cha;
if(cha>=48 && cha<=57)
cout<<" digit (number 0-9)"<<endl;
else if(cha>=65 && cha<=90)
cout<<" capital A-Z"<<endl;
else if(cha>=97 && cha<=122)
cout<<" small a-z"<<endl;
else
cout<<endl<<" special (@#$*) character";
getch();
return 0;
}