Example:
Master ()
{
float x = 654.32 1；
printf("%f，%e，%g "，x，x，x)；
}
Print output: 654.320984, 6.54 10e+002, 654.438+0 (of which 654.984 output is caused by memory storage error).
Extended data
layout/format character
Format characters are used to specify the data type and output format of the output item.
①d format: used to output decimal integers. There are the following usages:
%d: Output according to the actual length of integer data.
% md: m is the width of the specified output field. If the number of digits of data is less than m, the left end is filled with spaces; If it is greater than m, it is output according to the actual number of digits.
%ld: output long integer data.
②o format: output integers in unsigned octal format. Long integers can be output in "%lo" format. You can also specify the width of the field output in "%mo" format.
Example:
Master ()
{? int？ Answer? =? - 1;
printf("%d，%o "，？ First,? a)；
}
Operation results:-1, 177777
Program analysis:-1 (stored in the form of complement) in the memory unit is (111111/.
③x format: output integers in unsigned hexadecimal form. Long integers can be output in "%lx" format. You can also specify the field width and output it in "%mx" format.
④u format: output integers in unsigned decimal form. Long integers can be output in "%lu" format. You can also specify the field width to output in "%mu" format.
⑤c format: output a character.
⑥s format: used to output a string. There are several uses.
%s: For example, printf("%s ","China ") outputs" China "string (excluding double quotation marks).
%ms: The output string occupies m columns. If the length of the string itself is greater than m, it will break through the limit of obtaining m and output all strings. If the string length is less than m, the left blank is filled.
%-ms: If the length of the string is less than m, the string will be left and right filled with spaces within the range of m columns.
%m.ns: The output occupies m columns, but only the left n characters in the string are taken. These n characters are output on the right side of column M, with spaces on the left.
%-m.ns: where m and n have the same meaning, n characters are output on the left side of the range of m columns, and spaces are filled on the right side. If n>m is used, the value of n is automatically taken, which ensures the normal output of n characters.
⑦f format: used to output real numbers (including single precision and double precision) in decimal form. There are the following usages:
%f: No width is specified, all integer parts are output, and 6 decimal places are output.
%m.nf: the output * * * occupies m columns, including n decimal places, such as the left blank with a value width less than m.
%-m.nf: the output * * * occupies n columns, including n decimal places, for example, the width of the value is less than the right end of m to fill in spaces.
⑧e format: output real numbers in exponential form. The following forms can be used:
%e: The number part (also called mantissa) outputs 6 decimal places, and the exponent part occupies 5 or 4 digits.
The characters %m.ne and %-m.ne: m, n and "-"have the same meanings as before. Where n refers to the number of decimal places in the digital part of the data, and m refers to the width occupied by the whole output data.
⑨g format: automatically select the shorter output of F format or E format, and do not output meaningless zeros.
Reference link Baidu Encyclopedia? layout/format character