printf()？C/C++ codeprintf(%d,x)//命令参数%d，是指int类型，对否？printf(%i,x)//命令参数%i，是指什
printf()？
C/C++ codeprintf("%d",x); //命令参数%d，是指int类型，对否？printf("%i",x); //命令参数%i，是指什么类型。它与%d，有什么区别？
[解决办法]printf Type Field Characters
The type character is the only required format field ; it appears after any optional format fields. The type character determines whether the associated argument is interpreted as a character, string, or number. The types C and S, and the behavior of c and s with printf functions, are Microsoft extensions and are not ANSI-compatible.
Table R.3 printf Type Field Characters
Character Type Output Format
c int or wint_t When used with printf functions, specifies a single-byte character; when used with wprintf functions, specifies a wide character.
C int or wint_t When used with printf functions, specifies a wide character; when used with wprintf functions, specifies a single-byte character.
d int Signed decimal integer.
i int Signed decimal integer.
o int Unsigned octal integer.
u int Unsigned decimal integer.
x int Unsigned hexadecimal integer, using “abcdef.”
X int Unsigned hexadecimal integer, using “ABCDEF.”
e double Signed value having the form [ – ]d.dddd e [sign]ddd where d is a single decimal digit, dddd is one or more decimal digits, ddd is exactly three decimal digits, and sign is + or –.
E double Identical to the e format except that E rather than e introduces the exponent.
f double Signed value having the form [ – ]dddd.dddd, where dddd is one or more decimal digits. The number of digits before the decimal point depends on the magnitude of the number, and the number of digits after the decimal point depends on the requested precision.
g double Signed value printed in f or e format, whichever is more compact for the given value and precision. The e format is used only when the exponent of the value is less than –4 or greater than or equal to the precision argument. Trailing zeros are truncated, and the decimal point appears only if one or more digits follow it.
G double Identical to the g format, except that E, rather than e, introduces the exponent (where appropriate).
n Pointer to integer Number of characters successfully written so far to the stream or buffer; this value is stored in the integer whose address is given as the argument.
p Pointer to void Prints the address pointed to by the argument in the form xxxx:yyyy where xxxx is the segment and yyyy is the offset, and the digits x and y are uppercase hexadecimal digits.
s String When used with printf functions, specifies a single-byte–character string; when used with wprintf functions, specifies a wide-character string. Characters are printed up to the first null character or until the precision value is reached.
S String When used with printf functions, specifies a wide-character string; when used with wprintf functions, specifies a single-byte–character string. Characters are printed up to the first null character or until the precision value is reached.
[解决办法]%d %i printf似乎没区别。
scanf区别就大了：
d Decimal integer. Pointer to int.
i Decimal, hexadecimal, or octal integer. Pointer to int.
[解决办法]%i和%d完全等价，教科书上写着: d格式符(或i格式符). 用于输出十进制整数有符号int型的输出格式化控制符
控制字符 说明
%c 一个单一的字符
%d 一个十进制整数
%i 一个整数
%e, %f, %g 一个浮点数
%o 一个八进制数
%s 一个字符串
%x 一个十六进制数
%p 一个指针
%n 一个等于读取字符数量的整数
%u 一个无符号整数
%[] 一个字符集
%% 一个精度符号
[解决办法]
常用的也就那几个：
%s
%d
%c
%0x
%f
