foo.cc: In function 'void MergeSubs(int*, int)':
foo.cc:37:5: error: expected unqualified-id before 'int'
   37 |     int o=0;
      |     ^~~
foo.cc:44:13: error: 'o' was not declared in this scope
   44 |             o=a[i];
      |             ^
foo.cc:54:18: error: 'o' was not declared in this scope
   54 |         if(a[i]==o)
      |                  ^

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