Extracting a specific thing from a string

I have a string in the following format <a,b> which represents an edge in a directed graph (a is source and b is target) where 'a' and 'b' are also string themselves (for example a can be "Square" and b is "Circle").

I need to build a function which extracts a and another one which extracts b.

so the signature will be:

string getSource(String edge); //will return b
string getTarget(String edge); //will return a

I am using the std::string library to represent those strings.

I know that I need to find a way to find the ',' separating them in the middle of the string, and get rid of the '<' and'>'. But I couldn't find a function in std::string that will help me to do that.

How would you go about on doing this?

Thank you!