Printf Conversions Table

Table

Argument Character	Argument Type	Printed as
d, i	int	decimal number.
o	int	unsigned octal number (without a leading zero).
x, X	int	unsigned hexadecimal number (without a leading 0x or 0X), using abcdef or ABCDEF for 10, …, 15.
u	int	unsigned decimal number.
c	int	single character.
s	char *	print characters from the string until a \0 or the number of characters given by the precision.
f	double	[-]m.dddddd, where the number of d's is given by the precision (default 6).
e, E	double	[-]m.dddddde±xx or [-]m.ddddddE±xx, where the number of d's is given by the precision (default 6).
g, G	double	use %e or %E if the exponent is less than -4 or greater than or equal to the precision; otherwise use %f. Trailing zeros and a trailing decimal point are not printed.
p	void *	pointer (implementation-dependent representation).
%	no argument	print a %.

Optional Arguments

Following are the optional arguments you can use.

• Field Width (the minimum amount of character space required inside stdout).
  • Example: %11s makes a field width of 11 characters.
• Left Justification Flag
  • Example: %-10s. If the string[^1] to be printed is smaller than the field width required, the characters will be left justified instead of being right justified by default.
• Precision
  • Example: %.4s allows 4 characters (in case of strings[^1]) or 4 digits after the decimal point in float values to be printed.

#include <stdio.h>

int main () {

    const char* test = "hello world";

    printf(":%s:\n", test); // (1)!;
    printf(":%10s:\n", test); // (2)!;
    printf(":%.10s:\n", test); // (3)!;
    printf(":%-10s:\n", test); // (4)!;
    printf(":%.15s:\n", test); // (5)!;
    printf(":%-15s:\n", test); // (6)!;
    printf(":%15.10s:\n", test); // (7)!;
    printf(":%-15.10s:\n", test); // (8)!;

     return 0;
}

1. Prints :hello world:.
2. Prints :hello world:. The field width 10 was too small to fit in the string[^1] so some padding was needed.
3. Prints :hello worl:. String[^1] is only printed with 10 characters.
4. Prints :hello world:. There is no extra padding, therefore justification is irrelevant.
5. Prints :hello world:. More characters are allowed but string[^1] contains characters less than 15 in count.
6. Prints :hello world :. Minimum field width is 15, creating some padding around the string.[^1] Then the string[^1] is left justified.
7. Prints : hello worl:. Minimum field width is 15, creating some padding around the string.[^1] But only 10 characters are allowed due to precision.
8. Prints :hello worl :. Minimum field width is 15, creating some padding around the string.[^1] But only 10 characters are allowed due to precision and the string[^1] is left justified.

References

1. Read more about strings.