User defined exceptions

Package specification

    package vector_package is

        type vector is array (integer range <>) of float;

        function add (v1,v2 : vector) return vector;
        function scalar_product (v1,v2 : vector) return float;

        LENGTH_ERROR : exception;

    end vector_package;

Package body

    package body vector_package is

        function add (v1,v2 : vector) return vector is
        begin
            ...
        end add;

        function scalar_product (v1,v2 : vector) return float is
            sum  : float := 0.0;
            temp : vector(v1'RANGE);
        begin
            if v1'LENGTH /= v2'LENGTH then
                raise LENGTH_ERROR;
            end if;
            temp := v2;
            for i in v1'RANGE loop
               sum := sum + v1(i)*temp(i);
            end loop;
            return sum;
        end scalar_product;

    end vector_package;