如何在java中找到5个整数的中位数

Question

So I'm new to programming and my teacher wants us to find the medium using if statements (I've asked him but he's not really helping) we haven't learned scanner, loops, arrays, etc.. so all I know is bufferedReader, import.java.io & the basics . I've written out the if statements, but I'm still confused as to how to get it to output the median. The numbers are 1-5 so I know that the median is 3.. Here's what I have for the if statements.

        if (num1<num2) 
            System.out.println(num1 + "is less than" + num2);
        if (num1<num3)
            System.out.println(num1 + "is less than" + num3);
        if (num1<num4)
            System.out.println(num1 + "is less than" + num4);
        if (num1<num5)
            System.out.println(num1 + "is less than" + num5);
        if (num2>num1)
            System.out.println(num2 + "is greater than" + num1);    
        if (num2<num3)
            System.out.println(num2 + "is less than" + num3);
        if (num2<num4)
            System.out.println(num2 + "is less than" + num4);
        if (num1<num5)
            System.out.println(num1 + "is less than" + num5);
        if (num3>num1)
            System.out.println(num3 + "is greater than" + num1);
        if (num3>num2)
            System.out.println(num3 + "is greater than" + num2);
        if (num3<num4)
            System.out.println(num3 + "is less than" + num4);
        if (num3<num5)
            System.out.println(num3 + "is less than" + num5);
        if (num4>num1)
            System.out.println(num4 + "is greater than" + num1);
        if (num4>num2)
            System.out.println(num4 + "is greater than" + num2);
        if (num4>num3)
            System.out.println(num4 + "is greater than" + num3);
        if (num4<num5)
            System.out.println(num4 + "is less than" + num5);
        if (num5>num1)
            System.out.println(num5 + "is greater than" + num1);
        if (num5>num2)
            System.out.println(num5 + "is greater than" + num1);
        if (num5>num3)
            System.out.println(num5 + "is greater than" + num3);
        if (num5>num4)
            System.out.println(num5 + "is greater than" + num4);

Answer 1

I don't want to give you the answer; but here are a few tips.

if statements can take multiple conditions within the brackets such as:

if(a>b && b < 10){...}

You can also nest if statements within each other:

if(a>b){
   if(b<10){...}
}

And finally you can have an else condition, which will be executed when the condition is not met

if(a>b){
   ...
} else {
   ...
}

Of course these can all be combined together, nested ifs with multiple conditions and ifs nested into else blocks.

As I said, I don't want to give you the answer to your question as I don't believe that would be the most effective way of learning how to do this; but hopefully this is somewhat insightful and meaningful to your knowledge and understanding.

Answer 2

What if you have 555 numbers? Would you write again all possible combinations? That would literally take days.

Consider using some data structures, for example use array to store your numbers:

int[] array = new int[] {1, 2, 3, 4, 5};

The median would be element in the middle, 3.

int[] array2 = new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9};

The median would be 5 here.

To find median (let's assume the numbers are always in order) you can do something like this:

1. Find out what is the size of array (how many elements you have)
2. If size is odd, then the median is element in the middle
3. If size is even, then the median is a sum of two middle elements divided by 2

Example using array:

 int[] array = new int[]{1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
 int size = array.length;
    if (size % 2 == 1) { // odd
        System.out.println("Median: : " + array[size / 2]);
    } else { // even
        int sum = array[size / 2 - 1] + array[size / 2];
        System.out.println("Median: : " + (float) sum / 2);
    }

However, I have a feeling that even though this code is very simple, it can still be quite incomprehensible to you. I would strongly advise that you read about arrays and collections in Java - just to save you some time.