Program is to read the characters from keyboard:

Program is to read the characters from keyboard one by one stored in different files as upper constants, lower constants, others.txt

void main()

                  {

   clrscr();

   fstream fin1,fin2,fin3;

   fin1.open("lower.txt",ios::out);

   fin2.open("upper.txt",ios::out);

   fin3.open("others.txt",ios::out);

   char ch;

   cout<<" press enter to quit ";

  while ((ch=getche()) !=(char)13)

                {

                if (islower(ch))

                 fin1<

                else if(isupper(ch))

                 fin2<

                else

                 fin3<

                 }

   }