Cheat Sheet

# C All-in-One Desk Reference For C Beginer's

Written

## 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 |

## C Language Comparison Symbols

If you’re writing programs in C, you need to use comparison symbols. The symbols C uses, their meanings, and examples are shown in the following table:

Symbol | Meaning or Pronunciation | “True” Comparison Examples |
---|---|---|

< | Less than | 1 < 5 8 < 9 |

== | Equal to | 5 == 5 0 == 0 |

> | Greater than | 8 > 5 10 > 0 |

<= | Less than or equal to | 4 <= 5 8 <= 8 |

>= | Greater than or equal to | 9 >= 5 2 >= 2 |

!= | Not equal to | 1 != 0 4 != 3.99 |

## C Language Conversion Characters

When programming in C, you use conversion characters — the percent sign and a letter, for the most part — as placeholders for variables you want to display. The following table shows the conversion characters and what they display:

Conversion Character | Displays Argument (Variable’s Contents) As |
---|---|

%c | Single character |

%d | Signed decimal integer (int) |

%e | Signed floating-point value in E notation |

%f | Signed floating-point value (float) |

%g | Signed value in %e or %f format, whichever is shorter |

%i | Signed decimal integer (int) |

%o | Unsigned octal (base 8) integer (int) |

%s | String of text |

%u | Unsigned decimal integer (int) |

%x | Unsigned hexadecimal (base 16) integer (int) |

%% | (percent character) |

## C Language Escape Sequences

Programming in C is fast — all you have to do is type a short sequence of keystrokes — generally just two — to get a tab, a new line, a question mark, and more. The following table shows the sequences you need to accomplish a variety of tasks:

Sequence | Represents |
---|---|

\a | The speaker beeping |

\b | Backspace (move the cursor back, no erase) |

\f | Form feed (eject printer page; ankh character on the screen) |

\n | Newline, like pressing the Enter key |

\r | Carriage return (moves the cursor to the beginning of the line) |

\t | Tab |

\v | Vertical tab (moves the cursor down a line) |

\\ | The backslash character |

\’ | The apostrophe |

\” | The double-quote character |

\? | The question mark |

\0 | The “null” byte (backslash-zero) |

\x nnn | A character value in hexadecimal (base 16) |

\X nnn | A character value in hexadecimal (base 16) |

## C Language Keywords

The C programming language has just 32 keywords for you to build robust programs. With only 32 keywords, they all fit nicely into a short table. Use them wisely and well.

auto | double | int | struct |

break | else | long | switch |

case | enum | register | typedef |

char | extern | return | union |

const | float | short | unsigned |

continue | for | static | void |

default | goto | sizeof | volatile |

do | if | signed | While |

## C Language Numeric Data Types

When programming with C, keywords and variables go together like the 4th of July and fireworks, although with a bit less drama. The following table shows C keywords, their variable types, and their ranges:

## C Language Mathematical Symbols

Programming math functions with C is fairly straightforward: a plus sign works like any sixth-grader knows it should and does addition. The mathematical symbols and the function they serve in C are shown in the following table:

## No comments:

## Post a Comment