foo.cc:6:1: error: expected unqualified-id before '{' token
    6 | {
      | ^
foo.cc: In function 'void sel(int*, int)':
foo.cc:44:6: warning: unused variable 'i' [-Wunused-variable]
   44 |  int i,j,index,t;
      |      ^
foo.cc: In function 'void marges(int*, int, int)':
foo.cc:84:3: error: 'marge' was not declared in this scope; did you mean 'marges'?
   84 |   marge(a,start,mid,end);
      |   ^~~~~
      |   marges

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