How do I Search/Find and Replace in an STL string

Question

Is there a way to replace all occurrences of a substring with another string in std::string?

For instance:

void SomeFunction(std::string& str)
{
   str = str.replace("hello", "world"); //< I'm looking for something nice like this
}

Answer 1

The easiest way (offering something near what you wrote) is to use Boost.Regex, specifically regex_replace.

std::string has built in find() and replace() methods, but they are more cumbersome to work with as they require dealing with indices and string lengths.

Answer 2

Why not implement your own

void myReplace(std::string& str, const std::string& old, const std::string& new)
{
  size_t pos = 0;
  while((pos = str.find(old, pos)) != std::string::npos)
  {
     str.replace(pos, old.length(), new);
     pos += new.length();
  }
}

?

Answer 3

I believe this would work

It takes const char*'s as a parameter.

//params find and replace cannot be NULL
void FindAndReplace( std::string& source, const char* find, const char* replace )
{
   //ASSERT(find != NULL);
   //ASSERT(replace != NULL);
   size_t findLen = strlen(find);
   size_t replaceLen = strlen(replace);
   size_t pos = 0;

   //search for the next occurrence of find within source
   while ((pos = source.find( it, pos)) != std::string::npos)
   {
      //replace the found string with the replacement
      source.replace( pos, findLen, replace );

      //the next line keeps you from searching your replace string, 
      //so your could replace "hello" with "hello world" 
      //and not have it blow chunks.
      pos += replaceLen; 
   }
}