/in/foo.cc: In function 'long long int sum(int, int)':
/in/foo.cc:13:9: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
  return ans;
         ^~~
/in/foo.cc: In function 'void case1()':
/in/foo.cc:11:6: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
   ans+=a[p++];
   ~~~^~~~~~~~
/in/foo.cc:8:12: note: 'ans' was declared here
  long long ans;
            ^~~
/in/foo.cc: In function 'void setup_ta()':
/in/foo.cc:71:8: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
   ta[i]=sum(i-get_lowbits(i),i);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:71:8: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
   ta[i]=sum(i-get_lowbits(i),i);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
/in/foo.cc:8:12: note: 'ans' was declared here
  long long ans;
            ^~~