printf格式控制

ter	Type of Matching Argument	Auto-skip Leading White-Space	Example	Sample Matching Input
%	% (a literal, matched but not converted or assigned)	no	int anInt; scanf("%i%%", &anInt);	23%
d	int (See note)	yes	int anInt; long l; scanf("%d %ld", &anInt, &l);	-23 200
i	int (See note)	yes	int anInt; scanf("%i", &anInt);	0x23
o	unsigned int (See note)	yes	unsigned int aUInt; scanf("%o", &aUInt);	023
u	unsigned int (See note)	yes	unsigned int aUInt; scanf("%u", &aUInt);	23
x	unsigned int (See note)	yes	unsigned int aUInt; scanf("%d", &aUInt);	1A
a, e, f, g	float or double (See note)	yes	float f; double d; scanf("%f %lf", &f, &d);	1.2 3.4
c	char (See note)	no	char ch; scanf(" %c", &ch);	Q
s	array of char (See note)	yes	char s[30]; scanf("%29s", s);	hello
p	void (See note)	yes	int* pi; void* ptr; scanf("%p", &ptr); pi = (int*) ptr;	0064FE00
n	int (See note)	no	int x, cnt; scanf("X: %d%n", &x, &cnt);	X: 123  (cnt==6)
[	array of char (See note)	no	char s1[64], s2[64]; scanf(" %[^\n]", s1); scanf("%[^\t] %[^\t]", s1, s2);	Hello World field1   field2

scanf Format Specification Syntax

The control of input conversion is much simpler than for output conversions.  Any, all, or none of the following format modifiers may be used between the % and the final letter of the conversion specification.  Note these must appear (if at all) in the sequence shown here.  A · is used to indicate a space in the example output where spacing is not obvious.

%   *    maximum-field-width   length   Letter

 

Conversion Modifier	Description	Example	Matching Input	Results
*	Assignment Supression.  This modifier causes the corresponding input to be matched and converted, but not assigned (no matching argument is needed).	int anInt; scanf("%*s %i", &anInt);	Age:·29	anInt==29, return value==1
maximum field-width	This is the maximum number of character to read from the input.  Any remaining input is left unread.  (Always use this with "%s" and "%[...]" in all production quality code!  (No exceptions!)  You should use one less than the size of the array used to hold the result.)	int anInt; char s[10]; scanf("%2i", &anInt); scanf("%9s", s);	2345 VeryLongString	anInt==23, return value==1 s=="VeryLongS" return value==1
length modifier	This specifies the exact type of the matching arugment.  These length codes are the same as theprintf length modifiers, except as noted below:
	l  The same for integer conversions (d, i, o, u, x, or X conversion letters), specifies the matching argument is along int.  For floating point (a, A, e, E, f, F, g, or G conversion letters) an "l" has no effect in a printf, but with scanf, an ell specifies adouble.	double d; scanf("%lf", &d);	3.14	d==3.14 return value==1