foo.cc: In function 'int main()':
foo.cc:45:14: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
   for(int i;i=8;i++)
             ~^~
foo.cc:71:15: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
    for(int i;i=4;i++)
              ~^~
foo.cc:22:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&m);
  ~~~~~^~~~~~~~~~~~~~
foo.cc:25:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%s",s);
   ~~~~~^~~~~~~~
foo.cc:40:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d%d%d",&ed_x,&ed_y,&st_x,&st_y);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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