program calc use integral, only: trapezoid integer :: n, ios real :: a, b namelist /nml/ a, b, n write(*,*) ' Input interval (a,b) and division number (n) like' write(*,*) ' "nml a=0, b=10, n=100 /"' read(*, nml, iostat = ios) if ( ios == 0 ) then s = trapezoid(a,b,n) write(*,*) s else write(*,*) ' Error: input data is invalid.' stop end if end program calc