"CODE" 35122;
"REAL" "PROCEDURE" ARCCOS(X); "VALUE" X; "REAL" X;
"BEGIN" "REAL" U,V; U:= ABS(X); V:= (1-U)/(1+U);
    V:= "IF" V  =0 "THEN" 0 "ELSE"
        "IF" U+1=1 "THEN" 1.57079632679489 "ELSE"
                          2*ARCTAN(SQRT(V));
    ARCCOS:= "IF" X>0 "THEN" V "ELSE" 3.14159265358979 - V
"END" ARCCOS;
        "EOP"