Managing Save File Versions

1#include <fstream>
2#include <string>
3
4struct GameSave {
5  int Version{1}; // Current save format version
6  std::string PlayerName;
7  int Score;
8  // Other game data...
9};
10
11void SaveGame(const GameSave& Save) {
12  std::ofstream File{
13    "save.dat", std::ios::binary};
14  File.write(
15    reinterpret_cast<const char*>(
16      &Save. Version),
17    sizeof(Save.Version)
18  );
19  // Write remaining data...
20}

1GameSave LoadGame() {
2  GameSave Save;
3  std::ifstream File{
4    "save.dat", std::ios::binary};
5
6  // Read version first
7  int FileVersion{};
8  File.read(
9    reinterpret_cast<char*>(&FileVersion),
10    sizeof(FileVersion));
11
12  if (FileVersion == 1) {
13    // Handle version 1 format
14  } else if (FileVersion == 2) {
15    // Handle version 2 format
16  }
17
18  return Save;
19}

1GameSave ConvertSaveV1ToV2(
2  const GameSave& OldSave
3) {
4  GameSave NewSave;
5  NewSave.Version = 2;
6  NewSave.PlayerName = OldSave.PlayerName;
7  NewSave.Score = OldSave.Score;
8  
9  // Set default for new field
10  NewSave.Level = 1;
11  return NewSave;
12}