Memory Usage

Understanding how conversions affect memory usage is important, especially in games where performance matters. Let's break this down:

Converting to Bigger Types

When you convert a smaller type to a bigger type, you use more memory:

1#include <iostream>
2using namespace std;
3
4int main() {
5  // Small number types
6  char SmallNumber{65};          // Uses 1 byte
7  int BiggerNumber{SmallNumber}; // Uses 4 bytes
8
9  // The computer needs extra memory to
10  // store the same value!
11  cout << "Original char: " << SmallNumber;
12  cout << "\nAs integer: " << BiggerNumber;
13}

1Original char: A
2As integer: 65

Converting to Smaller Types

Going the other way can save memory but might lose information:

1#include <iostream>
2using namespace std;
3
4int main() {
5  // Big number type - uses 8 bytes
6  double BigDecimal{3.14159265359};
7
8  // Uses 4 bytes
9  float SmallDecimal{
10    static_cast<float>(BigDecimal)};
11
12  cout.precision(10);
13  cout << "Original:  " << BigDecimal << "\n";
14  cout << "Converted: " << SmallDecimal;
15}

1Original:  3.141592654
2Converted: 3.141592741

Memory Usage Guidelines

Here's what to remember about conversions and memory.

Converting to bigger types:

• Always safe - no data loss
• Uses more memory
• Might be slightly slower

Converting to smaller types:

• Might lose data
• Uses less memory
• Usually not worth the risk just to save memory

Most of the time, you should:

1. Choose the right type for your data from the start
2. Don't convert just to save memory unless you're sure you need to
3. Use uniform initialization to catch accidental conversions that might lose data