convert string to lower case

#include <string>
#include <algorithm>
using namespace std;

#include "utx.h"

string toLowerCase(const string& s)
  {
  string s1 = s;
  transform(s1.begin(), s1.end(), s1.begin(), tolower);
  return s1;
  }

void toLowerCaseInPlace(string& s)
  {
  transform(s.begin(), s.end(), s.begin(), tolower);
  }

TEST(lowercase)
  {
  string s = "aBc";
  utxassert(toLowerCase(s), "abc");
  utxassert(toLowerCase(string("cde")), "cde");
  }

TEST(lowercaseInPlace)
  {
  string s = "aBc";
  toLowerCaseInPlace(s);
  utxassert(s, "abc");
  s = "cde";
  toLowerCaseInPlace(s);
  utxassert(s, "cde");
  }