/in/foo.cc: In function 'int main()':
/in/foo.cc:12:1: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
 for(i=1;i<=n;i++)
 ^~~
/in/foo.cc:19:2: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
  for(i=1;i<=n;i++)
  ^~~
/in/foo.cc:23:16: warning: statement has no effect [-Wunused-value]
      {b[i][j+1]==0;
       ~~~~~~~~~^~~
/in/foo.cc:24:13: warning: statement has no effect [-Wunused-value]
    b[i][j-1]==0;
    ~~~~~~~~~^~~
/in/foo.cc:25:13: warning: statement has no effect [-Wunused-value]
    b[i+1][j]==0;
    ~~~~~~~~~^~~
/in/foo.cc:26:13: warning: statement has no effect [-Wunused-value]
    b[i-1][j]==0;
    ~~~~~~~~~^~~
/in/foo.cc:27:11: warning: statement has no effect [-Wunused-value]
    b[i][j]==0;
    ~~~~~~~^~~