boost::algorithm::replace_first — Replace first algorithm.
template<typename SequenceT, typename Range1T, typename Range2T> void replace_first(SequenceT & Input, const Range1T & Search, const Range2T & Format);
replace the first match of the search substring in the input with the format string. The input sequence is modified in-place.
Parameters:
Format
A substitute string
Input
An input string
Search
A substring to be searched for