# MATLAB - Basic Syntax

MATLAB environment behaves like a super-complex calculator. You can enter commands at the >> command prompt.

MATLAB is an interpreted environment. In other words, you give a command and MATLAB executes it right away.

## Hands on Practice

Type a valid expression, for example,

5 + 5

And press ENTER

When you click the Execute button, or type Ctrl+E, MATLAB executes it immediately and the result returned is:

ans = 10

Let us take up few more examples:

3 ^ 2 % 3 raised to the power of 2

When you click the Execute button, or type Ctrl+E, MATLAB executes it immediately and the result returned is:

ans = 9

Another example,

sin(pi /2) % sine of angle 90^{o}

When you click the Execute button, or type Ctrl+E, MATLAB executes it immediately and the result returned is:

ans = 1

Another example,

7/0 % Divide by zero

ans = Inf warning: division by zero

Another example,

732 * 20.3

ans = 1.4860e+04

MATLAB provides some special expressions for some mathematical symbols, like pi for π, Inf for ∞, i (and j) for √-1 etc. **Nan** stands for 'not a number'.

## Use of Semicolon (;) in MATLAB

Semicolon (;) indicates end of statement. However, if you want to suppress and hide the MATLAB output for an expression, add a semicolon after the expression.

For example,

x = 3; y = x + 5

y = 8

## Adding Comments

The percent symbol (%) is used for indicating a comment line. For example,

x = 9 % assign the value 9 to x

You can also write a block of comments using the block comment operators % { and % }.

The MATLAB editor includes tools and context menu items to help you add, remove, or change the format of comments.

## Commonly used Operators and Special Characters

MATLAB supports the following commonly used operators and special characters:

Operator | Purpose |
---|---|

+ | Plus; addition operator. |

- | Minus; subtraction operator. |

* | Scalar and matrix multiplication operator. |

.* | Array multiplication operator. |

^ | Scalar and matrix exponentiation operator. |

.^ | Array exponentiation operator. |

\ | Left-division operator. |

/ | Right-division operator. |

.\ | Array left-division operator. |

./ | Array right-division operator. |

: | Colon; generates regularly spaced elements and represents an entire row or column. |

( ) | Parentheses; encloses function arguments and array indices; overrides precedence. |

[ ] | Brackets; enclosures array elements. |

. | Decimal point. |

… | Ellipsis; line-continuation operator |

, | Comma; separates statements and elements in a row |

; | Semicolon; separates columns and suppresses display. |

% | Percent sign; designates a comment and specifies formatting. |

_ | Quote sign and transpose operator. |

._ | Nonconjugated transpose operator. |

= | Assignment operator. |

## Special Variables and Constants

MATLAB supports the following special variables and constants:

Name | Meaning |
---|---|

ans | Most recent answer. |

eps | Accuracy of floating-point precision. |

i,j | The imaginary unit √-1. |

Inf | Infinity. |

NaN | Undefined numerical result (not a number). |

pi | The number π |

## Naming Variables

Variable names consist of a letter followed by any number of letters, digits or underscore.

MATLAB is **case-sensitive**.

Variable names can be of any length, however, MATLAB uses only first N characters, where N is given by the function **namelengthmax**.

## Saving Your Work

The **save** command is used for saving all the variables in the workspace, as a file with .mat extension, in the current directory.

For example,

save myfile

You can reload the file anytime later using the **load** command.

load myfile