在 Java 中 sum [i++] 是什么意思？

我正在练习 Java，现在我遇到了一个问题。我无法理解这段代码是什么意思。有人会一步一步解释吗？

整个程序是一个两个二进制数相加的程序：

import java.util.Scanner;
public class Exercise17 {
 public static void main(String[] args)
 {
  long binary1, binary2;
  int i = 0, remainder = 0;
  int[] sum = new int[20];
  Scanner in = new Scanner(System.in);

   System.out.print("Input first binary number: ");
   binary1 = in.nextLong();
   System.out.print("Input second binary number: ");
   binary2 = in.nextLong();

   while (binary1 != 0 || binary2 != 0) 
  {
 sum[i++] = (int)((binary1 % 10 + binary2 % 10 + remainder) % 2);
 remainder = (int)((binary1 % 10 + binary2 % 10 + remainder) / 2);
  binary1 = binary1 / 10;
   binary2 = binary2 / 10;
   }
  if (remainder != 0) {
 sum[i++] = remainder;
 }
  --i;
  System.out.print("Sum of two binary numbers: ");
  while (i >= 0) {
  System.out.print(sum[i--]);
}
System.out.print("\n");  
}
}

告诉我这行是什么意思：

 sum[i++] = (int)((binary1 % 10 + binary2 % 10 + remainder) % 2);

sum[i++] 是什么意思，这整个语句是什么意思？