Type detection: Difference between revisions

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 end program input_type_detection_demo</pre>
+===Generic procedures (overloading)===
+In the following, the name ''print_text'' refers to two distinct subroutines. Which of the two is called depends on the type of the argument in the call; the decision is made ''at compile time''.
+<lang fortran>program type_detection_demo
+  implicit none
+  type text_block_t
+     character(len = 10000), allocatable :: lines(:)
+  end type text_block_t
+  interface print_text
+     procedure print_text_text_block_t
+     procedure print_text_file_unit
+  end interface print_text
+  type(text_block_t) :: text_block
+  integer :: i
+  allocate (text_block%lines(1:10))
+  do i = 1, 10
+     write (text_block%lines(i), '("i = ", I0)') i
+  end do
+  call print_text (text_block)
+  open (100, file = 'type_detection-fortran-2.f90', action = 'read')
+  call print_text (100)
+  close (100)
+contains
+  subroutine print_text_text_block_t (source)
+    class(text_block_t), intent(in) :: source
+    integer :: i
+    do i = lbound (source%lines, 1), ubound (source%lines, 1)
+       write (*, '(A)') trim (source%lines(i))
+    end do
+  end subroutine print_text_text_block_t
+  subroutine print_text_file_unit (source)
+    integer, intent(in) :: source
+    character(len = 10000) :: line_buffer
+    integer :: stat
+    read (source, '(A)', iostat = stat) line_buffer
+    do while (stat == 0)
+       write (*, '(A)') trim (line_buffer)
+       read (source, '(A)', iostat = stat) line_buffer
+    end do
+  end subroutine print_text_file_unit
+end program type_detection_demo</lang>
+{{out}}
+$ gfortran type_detection-fortran-2.f90 && ./a.out
+<pre>i = 1
+i = 2
+i = 3
+i = 4
+i = 5
+i = 6
+i = 7
+i = 8
+i = 9
+i = 10
+program type_detection_demo
+  implicit none
+  type text_block_t
+     character(len = 10000), allocatable :: lines(:)
+  end type text_block_t
+  interface print_text
+     procedure print_text_text_block_t
+     procedure print_text_file_unit
+  end interface print_text
+  type(text_block_t) :: text_block
+  integer :: i
+  allocate (text_block%lines(1:10))
+  do i = 1, 10
+     write (text_block%lines(i), '("i = ", I0)') i
+  end do
+  call print_text (text_block)
+  open (100, file = 'type_detection-fortran-2.f90', action = 'read')
+  call print_text (100)
+  close (100)
+contains
+  subroutine print_text_text_block_t (source)
+    class(text_block_t), intent(in) :: source
+    integer :: i
+    do i = lbound (source%lines, 1), ubound (source%lines, 1)
+       write (*, '(A)') trim (source%lines(i))
+    end do
+  end subroutine print_text_text_block_t
+  subroutine print_text_file_unit (source)
+    integer, intent(in) :: source
+    character(len = 10000) :: line_buffer
+    integer :: stat
+    read (source, '(A)', iostat = stat) line_buffer
+    do while (stat == 0)
+       write (*, '(A)') trim (line_buffer)
+       read (source, '(A)', iostat = stat) line_buffer
+    end do
+  end subroutine print_text_file_unit
+end program type_detection_demo</pre>
 =={{header|Go}}==