foo.cc: In function 'int main()':
foo.cc:22:14: error: 'pow' was not declared in this scope
   22 |   n[i]=(y-m)/pow(10,a-1-i);
      |              ^~~
foo.cc:18:24: warning: unused variable 'z' [-Wunused-variable]
   18 |  int y=atoi(x.c_str()),z,a=x.size();
      |                        ^

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