C Language Cheatsheet¶
Operator Precedence¶
Refer to cppreference.
Format String¶
The syntax of a format placeholder is
* Square brackets indicate optional parts of the placeholder.
Type¶
| Type | Description |
|---|---|
% |
Prints %. |
d |
Decimal signed int. |
u |
Decimal unsigned int. |
o |
Octal unsigned int. |
x, X |
Hexadecimal unsigned int. x for lower-case and X for upper-case. |
f |
Float-point types in fixed-point notation. |
e, E |
Float-point types in exponential notation: d.ddde±dd. e for lower-case "e" and E for upper-case. |
g, G |
Float-point types in either fixed-point or exponential notation, whichever is more appropriate for its magnitude. g for lower-case and G for upper-case. |
a, A |
Float-point in hexadecimal notation, starting with 0x or 0X. a for lower-case and A for upper-case. |
s |
null-terminated string. |
c |
char. |
p |
void* in an implementation-defined format. |
n |
Print nothing, but writes the number of characters written so far into an integer pointer parameter. |
Examples:
printf("%%"); // %
printf("%d", 123); // 123
printf("%d", -123); // -123
printf("%u", 123); // 123
printf("%u", -123); // 4294967173
printf("%o", 123); // 173
printf("%x", 123); // 7b
printf("%X", 123); // 7B
printf("%f", 123.456); // 123.456000
printf("%e", 123.456); // 1.234560e+02
printf("%E", 123.456); // 1.234560E+02
printf("%g", 123.456); // 123.456
printf("%G", 123.456); // 123.456
printf("%g", 123456789.123); // 1.23457e+08
printf("%G", 123456789.123); // 1.23457E+08
printf("%a", 123.456); // 0x1.edd2f1a9fbe77p+6
printf("%A", 123.456); // 0X1.EDD2F1A9FBE77P+6
printf("%s", "Hello"); // Hello
printf("%c", 'H'); // H
int a = 123;
printf("%p", &a); // 0x16d79b3d8
int n;
printf("Hello%n", &n); // Hello
printf("%d", n); // 5
Others¶
For further information, refer to Wikipedia.
Here are some common examples:
printf("[%5d]", 123); // [ 123]
printf("[%-5d]", 123); // [123 ]
printf("[%05d]", 123); // [00123]
printf("[%+5d]", 123); // [ +123]
printf("[%*d]", 5, 123); // [ 123] (dynamic width)
printf("[%.1f]", 123.456); // [123.5]
printf("[%10f]", 123.456); // [123.456000] (10 characters in total)
printf("[%10.5f]", 123.456); // [ 123.45600] (5 precision, 10 characters)
printf("[%010.5f]", 123.456); // [0123.45600] (5 precision, 10 characters)
Last update:
2023-10-19
Created: 2023-10-17
Created: 2023-10-17