foo.cc: In function 'void i_be_bigi(int, bigint&)':
foo.cc:24:6: warning: unused variable 'i' [-Wunused-variable]
   24 |  int i;
      |      ^
foo.cc: In function 'void chu(bigint&, int, bigint&)':
foo.cc:55:12: warning: 'qy' may be used uninitialized in this function [-Wmaybe-uninitialized]
   55 |  for(i=0;qy!=0;i++){
      |          ~~^~~

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