foo.cc:27:12: error: empty character constant
   27 |     res[n]='';
      |            ^~
foo.cc: In function 'int main()':
foo.cc:8:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    8 |     scanf("%d",&n);
      |     ~~~~~^~~~~~~~~
foo.cc:9:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    9 |     scanf("%s %s %s",a,b,c);
      |     ~~~~~^~~~~~~~~~~~~~~~~~

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