常量的默认类型如12.5,1e-3，float还是double？ [英] default type for constants like 12.5, 1e-3, float or double ?

问题描述

K& R表示浮点常数包含小数点

（123.4）或指数（1e-2）或两者兼有;他们的类型是双;除非

后缀。后缀f或F表示浮点常数; l或L

表示长双。


问题是这些常量默认为双倍，除非后缀为

with f或F？


提前致谢。


新手。

解决方案

Greenhorn写道：

K& R说浮点常数包含小数点
（123.4）或指数（1e-2）或两者兼而有之;他们的类型是双;除非
后缀。后缀f或F表示浮点常数; l或L
表示长双。

问题是这些常量默认为双，除非后缀
与f或F？

是的，默认情况下，未固定的浮点常数是双倍

float k = 12.4;


上面的变量k会被强制加倍吗？


greenhorn


blockquote>
blockquote> Greenhorn写道：

float k = 12.4;

上面的变量''k''会被强制类型强制加倍？

greenhorn

不，k仍然是声明的浮动。

双值12.4将被转换为浮点数，然后

分配给k。

Hi,
K&R says that "floating point constants contain a decimal point
(123.4) or an exponent (1e-2) or both; their type is double; unless
suffixed. The suffixes f or F indicate a float constant; l or L
indicate a long double."

the question is are these constants double by default unless suffixed
with f or F ?

Thanks in advance.

greenhorn.

解决方案

Greenhorn wrote:

Hi,
K&R says that "floating point constants contain a decimal point
(123.4) or an exponent (1e-2) or both; their type is double; unless
suffixed. The suffixes f or F indicate a float constant; l or L
indicate a long double."

the question is are these constants double by default unless suffixed
with f or F ?

Yes, unsuffixed floating point constants are double by default

float k = 12.4;

will the above variable ''k'' be type coerced to double ?

greenhorn

Greenhorn wrote:

float k = 12.4;

will the above variable ''k'' be type coerced to double ?

greenhorn

No, k remains a float as declared.
The double value 12.4 will be casted to a float, then
assigned to k.

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