foo.cc: In function 'int main()':
foo.cc:6:9: warning: unused variable 'a' [-Wunused-variable]
    6 |  int  n,a,m;
      |         ^
foo.cc:8:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    8 | scanf("%d",&n);
      | ~~~~~^~~~~~~~~
foo.cc:18:4: warning: 'm' may be used uninitialized in this function [-Wmaybe-uninitialized]
   18 | m=m*10+n%10;
      |   ~^~~

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