/in/foo.cc: In function 'int main()':
/in/foo.cc:23:27: warning: operation on 'm' may be undefined [-Wsequence-point]
  while(scanf("%d%d%lf",&a[++m].x,&a[m].y,&a[m].z)!=EOF);
                           ^~~
/in/foo.cc:23:27: warning: operation on 'm' may be undefined [-Wsequence-point]