/in/foo.cc: In function 'int main()':
/in/foo.cc:47:9: error: 'base' was not declared in this scope
   47 |         base.c[i][i] = 1;
      |         ^~~~
/in/foo.cc:49:5: error: 'res' was not declared in this scope
   49 |     res.c[1][1]=1;//初始化
      |     ^~~