subroutine print_matrix(matrix)
    integer, intent(in) :: matrix(4,4)
    integer x

    do x = 1,4
        write(*,*) matrix(x,1:4)
    end do

end subroutine

program test
    implicit none
    integer matrix(4,4)

    matrix(1:4,1:4) = 0

    call print_matrix(matrix)

end program test