浮点数转字符串的问题

[你怎么了熊吉]

我现在用QString::number(double)转，但是有个问题，比如输入100.00，输出的就是100，我想强制保留小数点后两位，应该用什么函数？

[xcyl]

QString::number(yourDouble, '.', 2);

[_Gx]

QString QString::number(double n, char format = 'g', int precision = 6) [static]
Returns a string equivalent of the number n, formatted according to the specified format and precision. See Argument Formats for details.

Unlike QLocale::toString(), this function does not honor the user's locale settings.

See also setNum() and QLocale::toString().

Argument Formats

In member functions where an argument format can be specified (e.g., arg(), number()), the argument format can be one of the following:

Format	Meaning
e	format as [-]9.9e[+|-]999
E	format as [-]9.9E[+|-]999
f	format as [-]9.9
g	use e or f format, whichever is the most concise
G	use E or f format, whichever is the most concise
A precision is also specified with the argument format. For the 'e', 'E', and 'f' formats, the precision represents the number of digits after the decimal point. For the 'g' and 'G' formats, the precision represents the maximum number of significant digits (trailing zeroes are omitted).

关键是第二个参数应该传什么,如果是默认的g是得不到你要的结果的,第三个参数是你想要保留的小数点后面的位数

[你怎么了熊吉]

引用 2 楼 q245879 的回复:

QString QString::number(double n, char format = 'g', int precision = 6) [static]
Returns a string equivalent of the number n, formatted according to the specified format and precision. See Argument Formats for details.

Unlike QLocale::toString(), this function does not honor the user's locale settings.

See also setNum() and QLocale::toString().

Argument Formats

In member functions where an argument format can be specified (e.g., arg(), number()), the argument format can be one of the following:

Format	Meaning
e	format as [-]9.9e[+|-]999
E	format as [-]9.9E[+|-]999
f	format as [-]9.9
g	use e or f format, whichever is the most concise
G	use E or f format, whichever is the most concise
A precision is also specified with the argument format. For the 'e', 'E', and 'f' formats, the precision represents the number of digits after the decimal point. For the 'g' and 'G' formats, the precision represents the maximum number of significant digits (trailing zeroes are omitted).

关键是第二个参数应该传什么,如果是默认的g是得不到你要的结果的,第三个参数是你想要保留的小数点后面的位数

第三个参数不是有效数字吗？ 第二个我就是这个列表看不明白，其它的选项好像是科学计数法吧？

[你怎么了熊吉]

引用 1 楼 cai6811376 的回复:

QString::number(yourDouble, '.', 2);

真的可以！ 求指教，第二个参数它给的选项不是'e','E','f','G'这些吗？？

[xcyl]

引用 4 楼 czarten 的回复:

[quote=引用 1 楼 cai6811376 的回复:] QString::number(yourDouble, '.', 2);

真的可以！ 求指教，第二个参数它给的选项不是'e','E','f','G'这些吗？？[/quote] 其实改用QString::number(yourDouble, 'f', 2);的