Overloading constructor with 2 same datatype members

Question

lets say i have a class with two std::string member and one int value, like:

class DataGroup final {
 public:
  explicit DataGroup (const std::vector<int>& groupNr,
                                   const std::string& group1,
                                   const std::string& group2)
      : groupNr(groupNr)
      , group1(group1)
      , group2(group2){};

  std::vector<int> groupNrs{};
  std::string group1{};
  std::string group2{};
};

Can i somehow have 2 overloaded constructors where one will initialize groupNr and group1, and other ctor initializes groupNr and group2 ? One of the strings not initialized in ctor call would be empty string then.

Answer 1

There are several way to have expected behavior:

• Named constructor

  class DataGroup final {
  public:
      // ...
      static DataGroup Group1(const std::vector<int>& groupNr,
                        const std::string& group)
        { return DataGroup{groupNr, group, ""}; }
      static DataGroup Group2(const std::vector<int>& groupNr,
                        const std::string& group)
        { return DataGroup{groupNr, "", group}; }
  
      // ...
  };
  
  DataGroup d = DataGroup::Group2({1, 2}, "MyGroup");
  

• Tagged constructor

  struct group1{};
  struct group2{};
  class DataGroup final {
  public:
      // ...
      DataGroup(group1, const std::vector<int>& groupNr,
                        const std::string& group) : DataGroup{groupNr, group, ""} {}
      DataGroup(group2, const std::vector<int>& groupNr,
                        const std::string& group) : DataGroup{groupNr, "", group} {}
  
      // ...
  };
  
  DataGroup d{group2{}, {1, 2}, "MyGroup");
  

• named parameters (see there for possible implementation)

  // ...
  DataGroup d{groupNr = {1, 2}, group2 = "MyGroup");