Different types of comparables

when implementing the comparator interface to achieve natural ordering of objects :

say if we had the class Account:

class Account
{
   Account(String name, int id) 
   int balance() 
   void deposit(int n)
}

we wanted to sort the Account balances of two accounts in order

whats the diffrence between these two methods?

public class comparebalances implements Comparable <Account>
{

     public int compare (Account acc1, Account acc2)
     {
       return acc1.balance()-acc2.balance();
     }

}

public class comparebalances implements Comparable <Account>
{

     public int compare (Account acc1, Account acc2)
     {
         if (acc1.balance()> acc2.balance())
            return 1;
         else if (acc1.balance()< acc2.balance())
            return -1;
         else if (acc1.balance()==acc2.balance())
            return 0;
     }

}

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第二个更安全，因为第一个可以提供极端值的错误结果（整数溢出）。

---

As Puce already wrote, the second is safer where Integer overflow would give you unexpected output. If you want it short and safe at the same time, you can write:

return Integer.compare(acc1.balance(), acc2.balance());

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