When to Use Small Integer Types

1#include <iostream>
2using namespace std;
3
4int main() {
5  // Using regular int for everything (wasteful)
6  int Health{100};       // 4 bytes
7  int Level{1};          // 4 bytes
8  int Strength{15};      // 4 bytes
9  int Intelligence{12};  // 4 bytes
10  // Total: 16 bytes per character
11
12  // Using appropriate sizes
13  // 2 bytes (max 32,767 is plenty)
14  int16_t BetterHealth{100};
15  // 1 byte (max 127 is enough)
16  int8_t BetterLevel{1};      
17  // 1 byte (max 127 is enough)
18  int8_t BetterStrength{15};
19  // 1 byte (max 127 is enough)
20  int8_t BetterIntelligence{12};
21  // Total: 5 bytes per character
22
23  // If your game has 1000 characters, you save:
24  cout << "Memory saved per 1000 characters: "
25    << (16 - 5) * 1000 << " bytes";
26}

1#include <iostream>
2using namespace std;
3
4int main() {
5  // Each color component only needs
6  // values 0-255
7  uint8_t Red{255};  // Perfect fit!
8  uint8_t Green{128};
9  uint8_t Blue{64};
10
11  // Using regular int would waste 3 bytes
12  // per color component!
13  // Uses 4 bytes instead of 1
14  int WastefulRed{255};
15  int WastefulGreen{128};
16  int WastefulBlue{64};
17
18  cout << "Memory used for one color"
19          " (efficient): "
20    << sizeof(Red) + sizeof(Green) + sizeof(Blue)
21    << " bytes\n";
22
23  cout << "Memory used for one color"
24    " (wasteful): "
25   << sizeof(WastefulRed)
26    + sizeof(WastefulGreen)
27    + sizeof(WastefulBlue)
28   << " bytes";
29}