foo.cc: In function 'std::__cxx11::string yasuo(std::__cxx11::string)':
foo.cc:11:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i=1;i<str1.length();i++)
               ~^~~~~~~~~~~~~~
foo.cc:16:8: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    if(i== str1.length()-1)str2 = str2 + to_string(j);
       ~^~~~~~~~~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:29:19: warning: unused variable 'ans' [-Wunused-variable]
  char s[1000]={0},ans[1000]={0};
                   ^~~
foo.cc:30:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%s",s); 
     ~~~~~^~~~~~~~

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