// charchang.cpp

#include <iostream.h>
#include <ctype.h>

int main()
{
  char a;

  do
   {
      cout << "Enter a upper or lowercase character\n";
      cin >> a;
      
      if( ! isalpha(a))
       {
          cout << "The character must be a letter\n";
       }
    } while( ! isalpha(a));

  if(islower(a))
   {
      cout << "The character " << a << " is lower case\n";
      cout << a << " converted to " << "Uppercase ";
      a = toupper(a);
      cout << a;
    }
   else
    {
       cout << "The character " << a << " is Uppercase\n";
       cout << a << " converted to " << "lowercase is ";
       a = tolower(a);
       cout << a
    } 

  return 0;
}

#include <iostream>
#include <cctype>

using namespace std;

int main()
{
	char a;

	do
	{
		cout << "Enter a upper or lowercase character: ";
		cin >> a;

		if(!isalpha(a))
		{
			cout << "The character must be a letter" << endl;
		}
	}
	while(!isalpha(a));

	if(islower(a))
	{
		cout << "The character '" << a << "' is lowercase" << endl;
		cout << a << " converted to " << "uppercase is" << (char)toupper(a) << endl;

	}
	else
	{
		cout << "The character '" << a << "' is uppercase" << endl;
		cout << a << " converted to " << "lowercase is " << (char)tolower(a) << endl;

	}

	return 0;
}