Replace AlphaNumeric Characters

I'm doing a prog that take the user input and prefixes each alpa numeric character and the '.' character, with "*jl" otherwise it leaves it alone.
It works, the problem is it doesn't do it for uppercase, how I can modifly it so that it converts the user input cin to all lower case?

cin.get().toLowerCase() isn't working, I saw that somewhere...

Code:

 
#include <iostream>
 
#include <iomanip>
 
#include <string>
 
#include <algorithm>
 
using std::cout; 
 
using std::string; using std::cin;
 
string alphaNumericData = "abcdefghijklmnopqrstuvwxyz.0123456789";
 
string e = "*jl";
 
int main()
 
{
 
char ch;
 
while ( (ch = cin.get()) != EOF){
 
unsignedint loc = alphaNumericData.find( ch, 0 );
 
if( loc != string::npos )
 
cout << e + ch;
 
else cout << ch; 
 
}
 
return 0;
 
}
 

There's tolower function...you can make use of it....
Prototype:
int tolower( int c );
header file required
<cstdlib> or <ctype>

>the problem is it doesn't do it for uppercase
That's because your search string doesn't include upper case letters. You can add them manually like you did with the lower case letters, or use tolower as mentioned above. Alternatively, the cctype header also declares isalnum, which does exactly what you want and you can get rid of the search string entirely, and the program will very likely be faster because the is* functions typically use a table lookup instead of a sequential search:

Code:

#include <iostream>
#include <cctype>
#include <string>

namespace {
  const std::string repl ( "*jl" );
}

int main()
{
  std::string s;

  while ( getline ( std::cin, s ) ) {
    std::string::iterator i = s.begin();
    std::string result;

    while ( i != s.end() ) {
      if ( isalnum ( *i ) )
        result += repl;
      result.push_back ( *i++ );
    }

    std::cout << s << '\n';
    std::cout << result << '\n';
  }
}

well what I didn't wasn't efficient, but it works. I put in

Code:

while ( (ch = cin.get()) != EOF){
ch = tolower(ch); 
unsignedint loc = alphaNumericData.find( ch, 0 );