foo.cc: In function ‘int read()’:
foo.cc:20:5: warning: this ‘while’ clause does not guard... [-Wmisleading-indentation]
   20 |     while(ch>=48&&ch<=57)
      |     ^~~~~
foo.cc:22:9: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the ‘while’
   22 |         return x*f;
      |         ^~~~~~
foo.cc: In function ‘int bu(int, int)’:
foo.cc:132:20: warning: suggest parentheses around ‘+’ inside ‘>>’ [-Wparentheses]
  132 |         int mid = l+r>>1;
      |                   ~^~