forth locals with vocabularies

locals.fd

vocabulary quadratic also quadratic definitions

vocabulary fdiscriminant also fdiscriminant definitions
fvariable a
fvariable b
fvariable c
previous definitions also fdiscriminant

\ calculate the discriminant (b^2 - 4ac)
: fdiscriminant ( a b c -- n )
   c f! b f! a f!
   b f@ fdup f*   a f@ c f@ f*   4e f*   f-
;
previous

: solutions? ( a b c -- )
   fdiscriminant
   fdup 0e f= if cr ." 1 solution" fdrop exit then
        0e f> if cr ." 2 solutions" fdrop exit then
   cr ." No real solutions"
;

\ Example usage:
\ 9e -12e 4e quadratic solutions? 
\ 1 solution ok