>> help for

 FOR    Repeat statements a specific number of times.
    The general form of a FOR statement is:
  
       FOR variable = expr, statement, ..., statement END
  
    The columns of the expression are stored one at a time in
    the variable and then the following statements, up to the
    END, are executed. The expression is often of the form X:Y,
    in which case its columns are simply scalars. Some examples
    (assume N has already been assigned a value).
  
         FOR I = 1:N,
             FOR J = 1:N,
                 A(I,J) = 1/(I+J-1);
             END
         END
  
    FOR S = 1.0: -0.1: 0.0, END steps S with increments of -0.1
    FOR E = EYE(N), ... END  sets E to the unit N-vectors.
 
    The BREAK statement can be used to terminate the loop prematurely.
 
    See also IF, WHILE, SWITCH, BREAK, END.

>> help while

 WHILE  Repeat statements an indefinite number of times.
    The general form of a WHILE statement is:
  
       WHILE expression
         statements
       END
  
    The statements are executed while the real part of the expression
    has all non-zero elements. The expression is usually the result of
    expr rop expr where rop is ==, <, >, <=, >=, or ~=.
 
    The BREAK statement can be used to terminate the loop prematurely.
 
    For example (assuming A already defined):
  
            E = 0*A; F = E + eye(size(E)); N = 1;
            while norm(E+F-E,1) > 0,
               E = E + F;
               F = A*F/N;
               N = N + 1;
            end
 
    See also FOR, IF, SWITCH, BREAK, END.

>> help break

 BREAK Terminate execution of WHILE or FOR loop.
    BREAK terminates the execution of FOR and WHILE loops.
    In nested loops, BREAK exits from the innermost loop only.

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