Add Linear Search in Fortran (#5159)

Author: leoraggy

archive/f/fortran/linear-search.f95

@@ -0,0 +1,54 @@
+Program linearsearch
+    implicit none
+
+    character(len=256) :: input1
+    character(len=10) :: input2
+    integer :: key
+    integer, dimension(5) :: array
+    logical :: searched
+    integer :: io_status
+
+    if(command_argument_count() < 2) call usage()
+
+    call get_command_argument(1, input1)
+    call get_command_argument(2,input2)
+
+    if(input1 == "") call usage()
+
+    read(unit=input1, fmt=*, iostat=io_status) array
+    read(unit=input2, fmt=*, iostat=io_status) key
+    
+    searched = exists(array,key)
+
+    if (searched) then
+        print '(a)', 'true'
+    else
+        print '(a)', 'false'
+    end if
+
+    contains
+
+    pure function exists(array, key) result(answer)
+        implicit none
+        INTEGER :: i
+        integer, intent(in) :: key
+        integer, intent(in) :: array(:)
+        logical :: answer
+
+        answer = .false.
+
+        do i = 1, size(array), 1
+            if(array(i) == key) then
+                answer = .true.
+                return
+            end if
+        end do
+
+    end function exists
+
+subroutine usage()
+    write(*,'(a)') "Usage: please provide a list of integers (""1, 4, 5, 11, 12"") and the integer to find (""11"")"
+    stop
+end subroutine usage
+
+End Program linearsearch