依次获得最大和第二大数字

Question

Help me understand the last portion of this code that aims to print the largest and second largest number in a sequence. What I am not fully understanding is, what is the need for the else if statement? with the code:

 if (input > largest) {
        secondLargest = largest;
        largest = input;

should that not do the job proper? it checks if input is greater than the largest number, sets the second Largest to the previous largest number. and update the new largest number with the one user inputed.

So what exactly is the purpose of this line of code then? and any reason the integers largest and secondLargest is set to -1 and not just 0 , has it to do with the sentinel that breaks the program is set to 0 ?

} else if (input > secondLargest) {
    secondLargest = input;

.

 int largest = -1;
  int secondLargest = -1;
  while (true) {
     int input = readInt(" ? ");
     if (input == SENTINEL) break;
     if (input > largest) {
        secondLargest = largest;
        largest = input;
     } else if (input > secondLargest) {
        secondLargest = input;
     }

Answer 1

Try your program with the sequence

    1 2 3 5 4

If you omit else if (input > secondLargest) { secondLargest = input; } else if (input > secondLargest) { secondLargest = input; } then result will be largest=5 and secondLargest=3, that is incorrect.

Answer 2

该else if代码处理情况下， input下降的当前值之间的largest和secondLargest 。

Answer 3

该else if部分是，在情况的input比不大于largest ，但大于secondLargest时， secondLargest应该改变，即使largest也不会。