Thread: toupper() & tolower() problem?

The following code converts the string copied to uppercase and then to lowercase again.

Code:

// Convert a string to uppercase & lowercase

#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cctype>

using namespace std;

int main()
{
 char str[80];
 int i;
 
 strcpy(str, "This is copied to str");
 for(i=0;str[i];i++)
                    str[i]=toupper(str[i]);
 cout << str;
 
 for(i=0;str[i];i++)
                    str[i]=tolower(str[i]);
 
 cout << "\nOriginal str was ( " << str << " )\n\n";
 
system("pause");
return 0;

}

The problem is I cannot make it work without a second for loop. I don't want to use the second for loop, instead any other way if possible.