问题
What does %.8Ff format specifier in printf do?
What does F mean?
回答1:
According to the manual:
The F conversion specifier produces "INF", "INFINITY", or "NAN" instead of "inf", "infinity", or "nan", respectively.
In your format string %.8Ff, the f is treated as a literal character and printed as an f.
回答2:
One possible use of putting a literal f after the format specifier could be to print a string that's later to be parsed by a C or C++ compiler as a float constant instead of double constant.
来源：https://stackoverflow.com/questions/4011940/what-does-an-f-in-the-format-specifier-of-printf-mean