一个string不区分大小写查找的方法（函数）

size_t FindNoCase(string strSource, char* szTarget)
{
 if (strSource.empty())
 {
  return string::npos;
 }

 string strSub = szTarget;

 if (strSub.empty())
 {
  return string::npos;
 }

 for (string::iterator it = strSource.begin(); it != strSource.end(); ++it)
 {
  *it = tolower(*it);
 }

 for (string::iterator ite = strSub.begin(); ite != strSub.end(); ++ite)
 {
  *ite = tolower(*ite);   //do not change szTarget context.
 }

 return strSource.find(strSub);
}