What are the differences between data types int32, int64, and simply int?

In Go, the types int32, int64, and int differ in size and platform dependence:

• int32 — a signed integer type occupying 32 bits (4 bytes), with a value range from -2^31 to 2^31-1.
• int64 — a signed integer type occupying 64 bits (8 bytes), with a value range from -2^63 to 2^63-1.
• int — a signed integer type whose size depends on the platform architecture:
  • 32 bits on 32-bit systems
  • 64 bits on 64-bit systems

Using int is convenient for general cases where the exact size is not crucial, and you want to optimize for the architecture. If a specific size is important (e.g., for binary protocols, interaction with C, or data storage), int32 or int64 are used.

Example:

type MyStruct struct {
    ID   int64  // for unique identifiers with a large range
    Count int32 // for counters where 32 bits are sufficient
    Index int   // depends on the platform
}

Thus, int is platform-dependent, while int32 and int64 are fixed-size.