(C++) StrToUpper

std::string convert code snippet to convert a std::string to upper case.


#include <algorithm>

#include <cctype>

#include <string>



//From http://www.richelbilderbeek.nl/CppStrToUpper.htm

const std::string StrToUpper(std::string s)

{

  std::transform(s.begin(), s.end(), s.begin(),std::ptr_fun<int,int>(std::toupper));

  return s;

}

Note that in the C++ Builder IDE std::ptr_fun can be called without its template arguments. When using the G++ 4.4.1 compiler leaving out the template arguments results in the compile error No matching function for call to 'ptr_fun'.

StrToUpper using a for loop

StrToUpper can be implemented using a for loop, but prefer algorithm calls over hand-written loops [1][2]. View Exercise #9: No for-loops for other ways of replacing for-loops by algorithms.


#include <cctype>

#include <string>



//From http://www.richelbilderbeek.nl/CppStrToUpper.htm

const std::string StrToUpper(std::string s) //Not the preferred way

{

  const int sz = static_cast<int>(s.size());

  for(int i=0; i!=sz; ++i)

  {

    s[i] = std::toupper(s[i]);

  }

  return s;

}

References

Bjarne Stroustrup. The C++ Programming Language (3rd edition). 1997. ISBN: 0-201-88954-4. Chapter 18.12.1: 'Prefer algorithms to loops.
Scott Meyers. Effective STL. ISBN: 0-201-74962-9. Item 43: 'Prefer algorithm calls over hand-written loops'.

Go back to Richel Bilderbeek's C++ page.

Go back to Richel Bilderbeek's homepage.