foo.cc: In function 'int main()':
foo.cc:11:17: warning: comparison of integer expressions of different signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare]
   11 |    for(int i=0;i<strlen(xm);i++)
      |                ~^~~~~~~~~~~
foo.cc:15:10: warning: 'sum' may be used uninitialized in this function [-Wmaybe-uninitialized]
   15 |    cout<<sum;
      |          ^~~

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