/in/foo.cc: In function 'void decode(char*, int)':
/in/foo.cc:5:15: warning: comparison of constant ''E'' with boolean expression is always true [-Wbool-compare]
   if('A'<=a[i]<='E')
      ~~~~~~~~~^~~~~
/in/foo.cc:5:9: warning: comparisons like 'X<=Y<=Z' do not have their mathematical meaning [-Wparentheses]
   if('A'<=a[i]<='E')
      ~~~^~~~~~
/in/foo.cc:7:18: warning: comparison of constant ''E'' with boolean expression is always true [-Wbool-compare]
      if('F'<=a[i]<='E')
         ~~~~~~~~~^~~~~
/in/foo.cc:7:12: warning: comparisons like 'X<=Y<=Z' do not have their mathematical meaning [-Wparentheses]
      if('F'<=a[i]<='E')
         ~~~^~~~~~