The precision specifier indicates the desired number of decimal places. 精度說(shuō)明符指示所需的小數位數。
The round-trip specifier guarantees that a numeric value converted to a string will be parsed back into the same numeric value. 往返過(guò)程說(shuō)明符保證轉換為字符串的數值再次被分析為相同的數值。