foo.cc: In function 'int main()':
foo.cc:26:26: warning: comparison of integer expressions of different signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare]
   26 |            for (int i=0;i<strlen(s);i++)
      |                         ~^~~~~~~~~~
foo.cc:16:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   16 |     scanf("%d",&k);
      |     ~~~~~^~~~~~~~~

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