Printf output function, printf output

Printf output function, printf output

The printf function is called the format output function.

Format:

Printf (const char * _ Format ,...)

Printf ("format control string", output table column)
The format control string is used to specify the output format. The format control string can be a format string or a non-format string. The format string is a string starting with "%". It is followed by characters in different formats to indicate the type, format, length, and decimal places of the output data. For example:

• "% D" indicates output in decimal integer;
• "% Ld" indicates the output is a long integer in decimal format;
• "% C" indicates output based on bytes.

 

1) Type
The type character is used to indicate the type of output data. Its format characters and meanings are shown in the following table:

Format characters	Meaning
D	Outputs signed integers in decimal form (positive numbers do not output symbols)
O	Output an unsigned integer in octal format (no prefix 0 is output)
X, X	Output an unsigned integer in hexadecimal format (the Ox prefix is not output)
U	Returns an unsigned integer in decimal format.
F	Output Single and Double Precision Real Numbers in decimal form
E, E	Output Single and Double Precision Real Numbers in exponential form
G, G	Output Single and Double precision real numbers with a shorter output width in % f or % e
C	Output Single Character
S	Output string

 

2) Flag
The following table lists the four types of Logo characters:-, +, #, and space:

 

 

Logo	Meaning
-	The result is left aligned with a space on the right.
+	Output symbol (positive or negative)
Space	When the output value is positive, it is preceded by a space.
#	It has no effect on Class c, s, d, and u; For the o class, add the prefix o to the output; Add the prefix 0x to the output of Class x; The decimal point is given for Class e, g, and f when the result has decimal places.