/in/foo.cc: In function 'int main()':
/in/foo.cc:8:17: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
    8 |         if(x1==0&&x2==n||x1==n&&x2==0||y1==0&&y2==m||y1==m&&y2==0)//两个点在对面
      |            ~~~~~^~~~~~~
/in/foo.cc:8:45: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
    8 |         if(x1==0&&x2==n||x1==n&&x2==0||y1==0&&y2==m||y1==m&&y2==0)//两个点在对面
      |                                        ~~~~~^~~~~~~
/in/foo.cc:8:59: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
    8 |         if(x1==0&&x2==n||x1==n&&x2==0||y1==0&&y2==m||y1==m&&y2==0)//两个点在对面
      |                                                      ~~~~~^~~~~~~
/in/foo.cc:10:41: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   10 |                 if(!(x1==0&&y1==0&&x2==n&&y2==m||x1==n&&y1==m&&x2==0&&y2==0||x1==0&&y1==m&&x2==n&&y2==0||x1==n&&y1==0&&x2==0&&y2==m))
      |                      ~~~~~~~~~~~~~~~~~~~^~~~~~~
/in/foo.cc:10:97: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   10 |                 if(!(x1==0&&y1==0&&x2==n&&y2==m||x1==n&&y1==m&&x2==0&&y2==0||x1==0&&y1==m&&x2==n&&y2==0||x1==n&&y1==0&&x2==0&&y2==m))
      |                                                                              ~~~~~~~~~~~~~~~~~~~^~~~~~~
/in/foo.cc:10:125: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   10 |                 if(!(x1==0&&y1==0&&x2==n&&y2==m||x1==n&&y1==m&&x2==0&&y2==0||x1==0&&y1==m&&x2==n&&y2==0||x1==n&&y1==0&&x2==0&&y2==m))
      |                                                                                                          ~~~~~~~~~~~~~~~~~~~^~~~~~~
/in/foo.cc:12:25: error: 'ans' was not declared in this scope; did you mean 'abs'?
   12 |                         ans=x1+x2+y1+y2;
      |                         ^~~
      |                         abs
/in/foo.cc:7:13: warning: unused variable 'basic' [-Wunused-variable]
    7 |         int basic=0;
      |             ^~~~~