整数和浮点数(Integers and floating point numbers)

整数有多个进制

　　二进制0b开头

　　八进制0开头

　　十六进制0x开头　　0-9 A-F

浮点数

　　位数有限　　有限位数的数

　　离散

　　舍入误差　　有四舍五入

　　大约　　接近但不等于

　　尽量避免使用浮点数进行比较

金额用BigDecimal

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Integer has more than one base

Starting with binary 0b

Octal 0

Hex 0x start 0-9 A-F

Floating point number

Number of finite digits

Discrete

The rounding error is rounded

Approximately close to but not equal to

Try to avoid using floating-point numbers for comparison

金额用BigDecimal