foo.cc:1:13: error: too many decimal points in number
    1 | var a:array[1..1000]of longint;
      |             ^~~~~~~
foo.cc:1:1: error: 'var' does not name a type
    1 | var a:array[1..1000]of longint;
      | ^~~
foo.cc:3:1: error: 'n' does not name a type
    3 | n,i,j,k,sum:longint;
      | ^
foo.cc:5:1: error: 'begin' does not name a type
    5 | begin
      | ^~~~~
foo.cc:9:1: error: expected unqualified-id before 'for'
    9 | for i:= 1 to n do
      | ^~~
foo.cc:13:1: error: expected unqualified-id before 'for'
   13 | for i:=n-1 downto 1 do
      | ^~~
foo.cc:18:1: error: 'sum' does not name a type
   18 | sum:=0;
      | ^~~
foo.cc:20:1: error: expected unqualified-id before 'for'
   20 | for i:=1 to n do
      | ^~~
foo.cc:24:8: error: expected constructor, destructor, or type conversion before '(' token
   24 | writeln(sum);
      |        ^
foo.cc:26:1: error: 'end' does not name a type
   26 | end.
      | ^~~

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