# 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 90o
```

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
```

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

```ans = Inf
warning: division by zero
```

Another example,

```732 * 20.3
```

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

```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
```

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

```y =  8
```

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 % }.

## Commonly used Operators and Special Characters

MATLAB supports the following commonly used operators and special characters −

Operator Purpose
- 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
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.

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
```

```load myfile