foo.cc: In function 'void abc()':
foo.cc:24:8: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   mid=x+y>>1;
       ~^~
foo.cc:30:3: error: expected ';' before 'else'
   else if(a[mid]>b) y=mid-1
   ^~~~

自豪的采用 HydroJudge 进行评测(github.com/hydro-dev/HydroJudge)