浮点数

浮点数是由一个可选符号、一个或多个数字、一个小数点(可选)后跟一个或几个数字、可选后跟字母 eE 、可选后跟符号、可选后跟一个或者多个数字组成的数字。

没有小数点的数字是 整数.

[ sign ] digit [ digit [ ... ] ] . [ { digit [ digit [ ... ] ] } ] [ { e | E } [ sign ] digit [ digit [ digit [ ... ] ] ]

  • sign : + or -, if the sign is missing, it is presumed to be +.

  • digit : 0 through 9.

  • . : indicates the number is a floating point number rather than an 整数.

  • e or E : indicates the number has an exponent. The case is ignored. There must be at least one digit after the E or e, optionally preceded by a sign.

At least one digit must appear before the decimal point. Note that while no digits are required after the decimal point, at least one digit must follow an E or e if it is used.

If there is no decimal point and no exponant, then the number will be interpreted as an integer.

The following are all valid floating-point numbers:
0.0 +0.0 0. -0.0 0.0e+1 0.0e-1 0.e+0 0.0e0 0.0e-0 -0.0e-0 (all are the same 0.0) 0.7 -0.3  1.0 -1. 1. -1.0  37.16 -40.33  +1.5 -12.34 3.14159267 1.39e5 1.7E-3

The following are all the same:
1000000.0 1.E+7 1e7 1.0e7 10.0e6 0.100E8 10000000.0E-1

Gambas provides two different floating-point types:

Floating-Point Description Default value Size in memory
Single -1.7014118E-38 .. +1.7014118E+38 0.0 4 bytes
Float -8.98846567431105E-307 .. +8.98846567431105E+307 0.0 8 bytes

See also