Cheat Sheet

C All-in-One Desk Reference For Dummies Cheat Sheet

From C All-in-One Desk Reference For Dummies

By Dan Gookin

When working in the C programming language, you need to be familiar with how C does things — for example, its order of precedence, variable types, operators, and comparisons and their opposites.

Order of Precedence in C Programming Language

If you’re programming with C, you’re using operators — and knowing whether to read those operators from left to right or right to left means writing a C program that works and one that crashes. Use the information in the following table to determine the order of precedence in C:


C Language Variable Types

Whether you’re working with regular or unsigned variables in your C program, you need to know a bit about those various variables. The following table show C variable types, their value ranges, and a few helpful comments:


C Language Operators

In programming with C, you occasionally want to use common mathematical operators for common mathematical functions and not-so-common operators for logic and sequence functions. Here’s a look at C language operators to use:

Operator, Category, Duty Operator, Category, Duty Operator, Category, Duty
=, Assignment, Equals !=, Comparison, Is not equal to >, Bitwise, Shift bits right
+, Mathematical, Addition &&, Logical, AND ~, Bitwise, One’s complement
–, Mathematical, Subtraction ||, Logical, OR +, Unary, Positive
*, Mathematical, Multiplication !, Logical, NOT –, Unary, Negative
/, Mathematical, Division ++, Mathematical, Increment by 1 *, Unary, Pointer
%, Mathematical, Modulo –, Mathematical, Decrement by 1 &, Unary, Address
>, Comparison, Greater than &, Bitwise, AND sizeof, Unary, Returns the size of an object
>=, Comparison, Greater than or equal to |, Bitwise, Inclusive OR ., Structure, Element access
<, Comparison, Less than ^, Bitwise, Exclusive OR (XOR or EOR) ->, Structure, Pointer element access
<=, Comparison, Less than or equal to <<, Bitwise, Shift bits left ?:, Conditional , Funky if operator expression
==, Comparison, Is equal to

C Language Comparisons and Their Opposites

Programming in C, or any programming language, means building comparisons — greater and lesser than and equal to in various combinations. Get to know the comparisons C uses and their opposites:

If Comparision Else Statement Executed By This Condition
< >= Greater than or equal to
== != Not equal to
> <= Less than or equal to
<= > Greater than
>= < Less than
!= == Equal to