/in/foo.cc: In function 'int binary_search(int)':
/in/foo.cc:13:14: error: 'leaf' was not declared in this scope
  while(right-leaf>1)
              ^~~~
/in/foo.cc:19:11: error: 'leaf' was not declared in this scope
  if(abs(a[leaf]-t)<=abs(a[right]-t))
           ^~~~
/in/foo.cc:11:6: warning: unused variable 'lef' [-Wunused-variable]
  int lef=1;
      ^~~