program drvbisect
      integer limit, maxits, nobrac, noofit, solved, status
      real    f, lastx0, lastx1, resid, root, tol, x0, x1
      parameter (tol=1e-6, maxits=25)
      parameter (solved=0, limit=1, nobrac=2)
      external  bisect, f
      
      print *, 'Give two initial values that bracket the root'
      read *, x0, x1
      call bisect(f, inx0, inx1, tol, maxits,
     +            status, root, resid, noofit, lastx0, lastx1)
      
      if (status.eq.solved) write(*,2000) root, resid, noofit
      if (status.eq.limit)  write(*,2010) maxits, lastx0, lastx1
      if (status.eq.nobrac) write(*,2020) x0, x1
      
2000  format(1x,'Root = ', f10.6,' at which f(x) = ',f8.6
     +      /1x,'Converged after ', i2,' iterations')
2010  format(1x,'Not converged after ',i2,' iterations'
     +      /1x,'Current interval is ',f10.6,' to ', f10.6)
2020  format(1x,'Initial approximations, ',f10.6,' and ',f10.6,
     +          ', are on the same side of the root')
      
      end