# Octave Programming Tutorial/Writing functions

## Syntax

In Octave, function definitions use the following syntax:

```function [return value 1, return value 2, ... ] = name( [arg1, arg2, ...] )
body
endfunction
```

## Examples

### Factorial Function

The factorial function, which takes exactly one argument and returns one integer, is as follows.

```function result = factorial( n )
if( n == 0 )
result = 1;
return;
else
result = prod( 1:n );
endif
endfunction
```

### Save m-File

You can save the definition of the function in your working directory. Use the name of the function also for the filename - e.g. use the filename `factorial.m` for the definition of the function `factorial` .

### Maximum and Minimum of two integer Values

The following function, maxmin, returns the maximum and minimum value of two integers:

```function [max,min] = maxmin( a, b )
if(a >= b )
max = a;
min = b;
return;
else
max = b;
min = a;
return;
endif
endfunction
```

To call a function with multiple arguments, you specify multiple variables to hold the results. For example, one could write:

```[big,small] = maxmin(7,10);
```

After executing, the variable 'big' would store the value '10' and the variable 'small' would store '7'. If fewer than two variables are used to hold the result then fewer outputs are returned. Writing

```a = maxmin(13,5)
```

would store 13 in the variable 'a', and would discard the value of 5.