while (MATLAB Function Reference)

Repeat statements an indefinite number of times

Syntax

while expression
    statements 
end

Description

while

repeats statements an indefinite number of times. The statements are executed while the real part of expression has all nonzero elements.
expression is usually of the form

expression rop expression

where rop is ==, <, >, <=, >=, or ~=.

The scope of a while statement is always terminated with a matching end.

Examples

The variable eps is a tolerance used to determine such things as near singularity and rank. Its initial value is the machine epsilon, the distance from 1.0 to the next largest floating-point number on your machine. Its calculation demonstrates while loops:

eps = 1;
while (1+eps) > 1
    eps = eps/2;
end
eps = eps*2