GNU Octave Manual Version 3by John W. Eaton, David Bateman, Søren Hauberg Paperback (6"x9"), 568 pages ISBN 095461206X RRP £24.95 ($39.95) |

## 8.7 Increment Operators

*Increment operators* increase or decrease the value of a variable
by 1. The operator to increment a variable is written as `‘++’`. It
may be used to increment a variable either before or after taking its
value.

For example, to pre-increment the variable `x`, you would write
`++`

. This would add one to `x``x` and then return the new
value of `x` as the result of the expression. It is exactly the
same as the expression

.
`x` = `x` + 1

To post-increment a variable `x`, you would write

.
This adds one to the variable `x`++`x`, but returns the value that
`x` had prior to incrementing it. For example, if `x` is equal
to 2, the result of the expression

is 2, and the new
value of `x`++`x` is 3.

For matrix and vector arguments, the increment and decrement operators work on each element of the operand.

Here is a list of all the increment and decrement expressions.

`++`

`x`-
This expression increments the variable
`x`. The value of the expression is the*new*value of`x`. It is equivalent to the expression

.`x`=`x`+ 1 `--`

`x`-
This expression decrements the variable
`x`. The value of the expression is the*new*value of`x`. It is equivalent to the expression

.`x`=`x`- 1 `x`++-
This expression causes the variable
`x`to be incremented. The value of the expression is the*old*value of`x`. `x`---
This expression causes the variable
`x`to be decremented. The value of the expression is the*old*value of`x`.

ISBN 095461206X | GNU Octave Manual Version 3 | See the print edition |