foo.cc: In function 'int bfs()':
foo.cc:42:9: warning: statement has no effect [-Wunused-value]
    next.step;
    ~~~~~^~~~
foo.cc: In function 'int main()':
foo.cc:56:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&m);
  ~~~~~^~~~~~~~~~~~~~
foo.cc:59:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    scanf("%d",&data[i][j]);
    ~~~~~^~~~~~~~~~~~~~~~~~
foo.cc:62:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%d%d",&sx,&sy,&ex,&ey);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:64:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%c",&ch);
  ~~~~~^~~~~~~~~~
foo.cc:65:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%c",&ch);
  ~~~~~^~~~~~~~~~

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