string str = "I'm a fairy! abc xyz ABC XYZ";
int casechanged = 0;
 
cout << str;
    for(i = 0; i < str.length(); i++)
    {
          if(isUpper(str[i])) { str[i] = toLower(str[i]); casechanged = 1; }
          if(isLower(str[i]) && casechanged != 1) { str[i] = toUpper(str[i]);}
 
          casechanged = 0;
    }
    cout << str;
 
    for(i = 0; i < str.length(); i++)
    {
          if(isLower(str[i])) { str[i] = toUpper(str[i]); casechanged = 1; }
          if(isUpper(str[i]) && casechanged != 1) { str[i] = toLower(str[i]); }
 
          casechanged = 0;
    }
   cout << str;

#include <iostream>
#include <cctype>
 
using namespace std;
 
int main ()
{
	char letters[20];
	int i;
 
	cout << "Pease enter characters " << endl;
	cin >> letters;
 
	cout << letters << endl; //assignment said display the original
 
	for ( i = 0; letters[i]; i++ )
	{
		if ( isalpha(letters[i] ) )
		{
			if ( islower(letters[i] ) )
				letters[i] = (char) toupper( letters[i] );
			else //we know it's a letter, and not lowercase
				letters[i] = (char) tolower( letters[i] );
		}
		//don't do anything to non-alpha
	}
 
	//display the whole string, not one char at a time in the loop
	cout << letters << endl;  //the changed version
 
	cout << endl;
 
	return 0;
}