I want to create a string that contains many variables:

std::string name1 = "Frank";
std::string name2 = "Joe";
std::string name3 = "Nancy";
std::string name4 = "Sherlock";

std::string sentence;

sentence =   name1 + " and " + name2 + " sat down with " + name3;
sentence += " to play cards, while " + name4 + " played the violin.";

This should produce a sentence that reads

Frank and Joe sat down with Nancy to play cards, while Sherlock played the violin.

My question is: What is the optimal way to accomplish this? I am concerned that constantly using the + operator is ineffecient. Is there a better way?