foo.cc: In function 'void print(long long int)':
foo.cc:53:19: warning: array subscript has type 'char' [-Wchar-subscripts]
 while (x) a[++a[0]] = x%10,x/=10;
                   ^
foo.cc:55:15: warning: array subscript has type 'char' [-Wchar-subscripts]
 putchar(a[a[0]]+48);
               ^

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