/in/foo.cc: In function 'int main()':
/in/foo.cc:32:9: warning: this 'else' clause does not guard... [-Wmisleading-indentation]
         else mx=getnum(s);bool flag=0;
         ^~~~
/in/foo.cc:32:27: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'else'
         else mx=getnum(s);bool flag=0;
                           ^~~~
/in/foo.cc:39:44: warning: array subscript has type 'char' [-Wchar-subscripts]
                 if(s[0]=='F') {if(!vis[s[2]])stk[++top]=s[2],vis[s[2]]=1;else puts("ERR"),flag=1;}
                                            ^
/in/foo.cc:39:70: warning: array subscript has type 'char' [-Wchar-subscripts]
                 if(s[0]=='F') {if(!vis[s[2]])stk[++top]=s[2],vis[s[2]]=1;else puts("ERR"),flag=1;}
                                                                      ^
/in/foo.cc:40:49: warning: array subscript has type 'char' [-Wchar-subscripts]
                 else if(s[0]=='E')vis[stk[top--]]=0;continue;
                                                 ^
/in/foo.cc:40:17: warning: this 'else' clause does not guard... [-Wmisleading-indentation]
                 else if(s[0]=='E')vis[stk[top--]]=0;continue;
                 ^~~~
/in/foo.cc:40:53: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'else'
                 else if(s[0]=='E')vis[stk[top--]]=0;continue;
                                                     ^~~~~~~~
/in/foo.cc:45:28: warning: array subscript has type 'char' [-Wchar-subscripts]
                 if(vis[s[2]]) {puts("ERR");flag=1;continue;}
                            ^
/in/foo.cc:46:25: warning: array subscript has type 'char' [-Wchar-subscripts]
                 vis[s[2]]=1,stk[++top]=s[2];
                         ^
/in/foo.cc:54:83: warning: array subscript has type 'char' [-Wchar-subscripts]
                 if(top)    {if(!chang[top]) num--;else chang[top]=0;vis[stk[top--]]=0;}
                                                                                   ^