foo.cc: In function 'int main()':
foo.cc:9:10: error: expected unqualified-id before numeric constant
    9 |  int n,r,1=0,s=0;
      |          ^
foo.cc:13:5: error: 's' was not declared in this scope
   13 |     s=s+r*pow(2,i);
      |     ^
foo.cc:13:17: error: 'i' was not declared in this scope
   13 |     s=s+r*pow(2,i);
      |                 ^
foo.cc:17:8: error: 's' was not declared in this scope
   17 |  cout<<s;
      |        ^

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