问题:

Possible Duplicate:
Why are Hexadecimal Prefixed as 0x?

I just saw a comment a friend of mine made:

3x12=36
2x12=24
1x12=12
0x12=18

Which made me wonder..
Why did they choose 0x as prefix for hexadecimal numbers? Is there any history behind this decision?

回答1:

I think, because x comes from hex and 0 is to indicate that it is a number.

回答2:

0x means the number is probably hexadecimal. This applies in C/C++, and probalby other languages.

His comment is a joke. he starts with multiplication tables for the number 12, but when he gets to 0 he implies that 0x is not "0 multiplied by...", but instead is "hexadecimal" so 12 in hex is 18 in decimal.

回答3:

It's a joke on HEX numbers from WIKIPEDIA.

The first three are interpreted as multiplication, but in the last, "0x" signals Hexadecimal interpretation of 12, which is 18.

回答4:

'0x' means that the number that follows is in hexadecimal. It's a way of unambiguously stating that a number is in hex, and is a notation recognised by C compilers and some assemblers