foo.cc: In function 'int main()':
foo.cc:7:8: warning: unused variable 'm' [-Wunused-variable]
    7 |  int n,m=0,a,b,c;
      |        ^
foo.cc:8:3: warning: 'n' is used uninitialized in this function [-Wuninitialized]
    8 |  a=n%10;
      |  ~^~~~~

[Hydro](https://hydro.ac)提供评测服务