C++ find specific number in a string

I'm quite new to regular expressions. I have this string.

string s = media_type=video|key_frame=1|pkt_pts=1516999|pkt_pts_time=50.566633|pkt_dts=1516999|

I need to get 50.566633 value extracted using string operators and regular expressions in C++. Can some one suggest a way to do this?