What are the differences integer, cardinal, extended and int64 in Delphi?

In Delphi, Integer, Cardinal, Extended, and Int64 are different data types that represent integers or floating-point numbers with various ranges and precision. Here are the key differences between them:

• 1. **Integer:**
  – Represents signed 32-bit integers.
  – Range: -2147483648 to 2147483647.
  – Declaration: Integer.

• 2. **Cardinal:**
  – Represents unsigned 32-bit integers.
  – Range: 0 to 4294967295.
  – Declaration: Cardinal.

• 3. **Extended:**
  – Represents extended-precision floating-point numbers.
  – Extended precision provides a larger range and higher precision compared to Single or Double.
  – Typically a 10-byte (80-bit) floating-point number on most platforms.
  – Declaration: Extended.

• 4. **Int64:**
  – Represents signed 64-bit integers.
  – Range: -9223372036854775808 to 9223372036854775807.
  – Declaration: Int64.

It’s important to choose the appropriate data type based on your specific needs:

• – Use Integer or Cardinal when working with whole numbers within the 32-bit signed or unsigned range.
• – Use Int64 when dealing with larger integers, especially when the values may exceed the range of a 32-bit signed integer.
• – Use Extended when you need higher precision floating-point numbers. Note that Extended is not always supported on all platforms, and there may be differences in its precision depending on the platform.

Here’s a simple example:

Choose the data type that best fits the range and precision requirements of your application.