二进制、十进制、十六进制：开发者速查表

When debugging bytes, logs, or packet data, speed matters. This is the cheat sheet I wish every dev had open.

Core Mapping

• Binary is base-2.
• Decimal is base-10.
• Hex is base-16.

Hex is compact and maps cleanly to binary:

• 1 hex digit = 4 bits (one nibble)
• 2 hex digits = 8 bits (one byte)

Instant Nibble Table

Worked Examples

Example 1: Binary to Hex

11110000 -> split as 1111 0000 -> F0

Example 2: Hex to Binary

2A -> 2 is 0010, A is 1010 -> 00101010

Example 3: Binary to Decimal

00101010 = 32 + 8 + 2 = 42

Example 4: Decimal to Binary

42 = 32 + 8 + 2 -> 00101010

Common Developer Patterns

1. 0xFF as mask for one byte.
2. 0x0F and 0xF0 for low/high nibble operations.
3. Byte arrays shown in hex logs (DE AD BE EF style).

Practice Set

Try converting:

• 0x7F
• 10000000
• 255
• 0x2A
• 01010101

Use:

• Binary to Decimal
• Binary to Hex
• Base 2-62 Converter

References

• RFC 4648 (base encodings)
• MDN Number Systems