foo.cc: In function 'int main()':
foo.cc:7:6: warning: unused variable 'sum' [-Wunused-variable]
  int sum=0,a[50005];
      ^~~
foo.cc: At global scope:
foo.cc:19:2: error: expected unqualified-id before 'for'
  for(int i=1;i<=n;i++)
  ^~~
foo.cc:19:14: error: 'i' does not name a type
  for(int i=1;i<=n;i++)
              ^
foo.cc:19:19: error: 'i' does not name a type
  for(int i=1;i<=n;i++)
                   ^
foo.cc:21:2: error: 'cout' does not name a type
  cout<<c;
  ^~~~
foo.cc:22:2: error: expected unqualified-id before 'return'
  return 0;
  ^~~~~~
foo.cc:23:1: error: expected declaration before '}' token
 }
 ^

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