foo.cc: In function 'int main()':
foo.cc:7:2: error: expected primary-expression before ',' token
  ,i;
  ^
foo.cc:15:8: error: 'k' was not declared in this scope
  for(i=k-1;i>=0;1--)
        ^
foo.cc:15:18: error: lvalue required as decrement operand
  for(i=k-1;i>=0;1--)
                  ^~

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