Chapter 7 Exercise 28, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

*7.28 (Math: combinations) Write a program that prompts the user to enter 10 integers and displays all combinations of picking two numbers from the 10.

import java.util.Scanner;
 
 
public class ProgrammingEx7_28 {
 
 public static void main(String[] args) {
  Scanner input = new Scanner(System.in);
 
  System.out.print("Enter ten numbers:");
   
  int[] list1 = new int[10];
  for (int i = 0; i < list1.length; i++) {
   list1[i] = input.nextInt();
  }
   
   
  for (int i = 0; i < list1.length-1; i++) {
   for (int j = i+1; j < list1.length; j++) {
    System.out.print( list1[i] + "," + list1[j] + " ");
   }
   System.out.println();
  }
 
 }
 
}