# while

while keyword

## Description

The `while` clause must be terminated by `"end"`.

`while expr ,instructions,...[,else instructions], end`

`while expr do instructions,...[,else instructions], end`

`while expr then instructions,...[,else instructions], end`

Notes:

- The only constraint is that each `then` or `do` keyword must be on the same line line as `while` keyword.

- Keywords `then` or `do` can be replaced by a carriage return or a comma. For compatibility with Matlab it is also possible, but not recommended, to put a space between the end of the expression and the beginning of the first instruction.

- The optional `[,else instructions]` construction allows to gives `instructions` which are executed when `expr` expression becomes false.

According to the Code Conventions for the Scilab Programming Language it is recommended:

- Start each statement on a new line.

- Write no more than one simple statement per line.

- Break compound statements over multiple lines.

For example, use:

          i = 0
          while i<5
              disp("i");
              i = i + 1;
          end

rather than

          i = 0; while i<5 disp("i"); i = i + 1; end

Warning: the number of characters used to define the body of any conditional instruction (if while for or select/case) must be limited to 16k.

## Examples

    e=1; a=1; k=1;
    while norm(a-(a+e),1) > %eps,
        e=e/2;
        k=k+1;
    end
    e,k

## See Also

- for
- select
- break
- return
- pause