128 FUN Puzzles of Increasing Difficulty Where You Must Ask: Was that a copy, or was it a reference, and who last changed that value?Book 2 now has `std::swap` puzzles!Example puzzle:void run() {
char char_1{'t'};
char_1 = 'm';
auto &char_3 = char_1;
char_1 = 'u';
char char_5{'o'};
char_1 = 'c';
auto &char_7 = char_3;
char char_8{'l'};
auto &char_9 = char_1;
char_8 = 'k';
auto &char_11 = char_7;
char char_12{'l'};
print("{}{}{}{}{}", char_1, char_12, char_5, char_7, char_8);
}

// Answer (5): __ __ __ __ __