foo.cc: In function 'int main()':
foo.cc:23:11: warning: statement has no effect [-Wunused-value]
   23 |       r[y]==1;
      |       ~~~~^~~
foo.cc:25:11: warning: statement has no effect [-Wunused-value]
   25 |       r[y]==0;
      |       ~~~~^~~
foo.cc:31:8: error: 'y' was not declared in this scope
   31 |   if(r[y]==1)
      |        ^

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