exp.m

MODULE exp; 

IMPORT Out;

PROCEDURE exponent*(x,n: INTEGER):INTEGER;
VAR
     y,z,k: INTEGER; 

BEGIN
y := 1; 
z := x; 
k := n; 
     WHILE k > 0 DO


     	  WHILE k MOD 2 = 0 DO
     	       z := z*z; 
     	       k := k DIV 2; 
     	  END; 
     	  IF k MOD 2 = 1 THEN
     	       y := z*y;
     	       k := k-1;
     	  END;
     END;
     RETURN y;
END exponent;

BEGIN
Out.Int(exponent(13,8), 0);

END exp.