/in/foo.cc: In function 'int main()':
/in/foo.cc:17:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
     for(int i=1;i<=n;i++)scanf("%d",&a[i].x);a[n].y=a[1].x;
     ^~~
/in/foo.cc:17:46: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
     for(int i=1;i<=n;i++)scanf("%d",&a[i].x);a[n].y=a[1].x;
                                              ^