sprintf函数使用详解

tips:
1.函数包含在stdio.h文件中，使用#include<stdio.h>
2.函数声明：int sprintf( char *buffer, const char *format , [argument,...] );
3.主要功能是根据char *format定义格式输出到字符串缓冲区buffer

sprintf主要是依靠控制格式的字符串const char *format 来完成灵活的写入
format的用法跟printf函数的一样，下面介绍printf的format结构
format的结构 %[flags][width][.precision][length]specifier
1.specifier

specifier Output Example d or i Signed decimal integer 392 u Unsigned decimal integer 7235 o Unsigned octal 610 x Unsigned hexadecimal integer 7fa X Unsigned hexadecimal integer (uppercase) 7FA f Decimal floating point, lowercase 392.65 F Decimal floating point, uppercase 392.65 e Scientific notation (mantissa/exponent), lowercase 3.9265e+2 E Scientific notation (mantissa/exponent), uppercase 3.9265E+2 g Use the shortest representation: %e or %f 392.65 G Use the shortest representation: %E or %F 392.65 a Hexadecimal floating point, lowercase -0xc.90fep-2 A Hexadecimal floating point, uppercase -0XC.90FEP-2 c Character a s String of characters sample p Pointer address b8000000 n Nothing printed. The corresponding argument must be a pointer to a signed int.The number of characters written so far is stored in the pointed location. % A % followed by another % character will write a single % to the stream. %

2.flags

flags description - Left-justify within the given field width; Right

+ Forces to preceed the result with a plus or minus sign (+ or -) even for positive numbers. By default, only negative numbers are preceded with a - sign.
(space) If no sign is going to be written, a blank space is inserted before the value.
Used with o, x or X specifiers the value is preceeded with 0, 0x or 0X respectively for values different than zero.
Used with a, A, e, E, f, F, g or G it forces the written output to contain a decimal point even if no more digits follow. By default, if no digits follow, no decimal point is written.
0 Left-pads the number with zeroes (0) instead of spaces when padding is specified (see width sub-specifier).