就像“11”在基数10中表示“110”和“111”一样，“11”在基数16（即十六进制）中表示“116”和“111”--或者17在基数10中。

数字开头的0x表示编译器将以十六进制读取它。0x11 = 1 * 16 + 1 = 17

0x11 = 116^1 + 116^0 = 17（就像17 = 1 * 10^1 + 7 * 10^0一样）。

十六进制计数为16位，而不是10位。为了说明额外的6位数，它使用字母A到F。
从16进制和10进制的0开始计数：

0, 1, 2, 3, 4, 5, 6, 7, 8, 9,  A,  B,  C,  D,  E,  F, 10, 11 (base 16)
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 (base 10)

此外，要从基数16转换为基数10：
1116 = 1 * 16 + 1 = 1710

0x11 =   1 * 16^1 (16)
       + 1 * 16^0 ( 1)
     -----------------
      0x11        (17)

就像：

17 =   1 * 10^1 (10)
       + 7 * 10^0 ( 7)
     -----------------
        17        (17)

嗯，也许是因为0x11是十进制的17？

下面是一种简单的查看方法
128 64 32 16 8 4 2 1 =...的十进制值
0 0 0 1 0 0 0 1 =打开或关闭的布尔开关
把它们加在一起16 + 1 = 17

These answers are really confusing, I would suggest an easy way to understand. 

Hexadecimal base is 16

0x11 is 011 (simply remove x)

For 011 we have 3 digits right?
If we start from 0th position, these digits are:
 0th position(0 in 011),
 1st position (1 in 011)
 and 2nd position(again 1 in 011)

take positions in reverse order: 2,1,0

the calculation part

16^2 * value at first position(0th) = 16^2 * 0 = 0   
16^1 * value at second position (1st) = 16^1 * 1 = 16
16^0 * value at third position (2nd) = 16^0 * 1 = 1

adding all these answers will get 0 + 16 + 1 = 17