Linux上双重C描述符

Question

C中双重描述符是什么？当我使用

printf("%d",x) 

和x是double变量，它说一个警告，它%d expects an int argument, while x is double。

Answer 1

printf("%f", x); 

当x是double变量。

Answer 2

printf有相当多的格式说明符。这里是基本的：

%d print an int argument in decimal 
%ld print a long int argument in decimal 
%c print a character 
%s print a string 
%f print a float or double argument 
%e same as %f, but use exponential notation 
%g use %e or %f, whichever is better 
%o print an int argument in octal (base 8) 
%x print an int argument in hexadecimal (base 16) 
%% print a single %