Answer:
package b4;
import java.util.ArrayList;
import java.util.Scanner;
public class ToThePowerOf {
public static void main(String[] args) {
//Create an object of the scanner class to allow for user inputs
Scanner input = new Scanner(System.in);
// Since the number of persons are not known before hand,
// using arraylists to hold the names and ages is a better idea
// Arraylists are flexible
ArrayList<String> names = new ArrayList<>();
ArrayList<Integer> ages = new ArrayList<>();
// variable name to temporarily hold the current name that is being entered
String name = "";
// variable age to temporarily hold the current age that is being entered
int age = 0;
// creating an infinite loop
// loop will only end when the user enters a value of 0 for age
while (true) {
System.out.println("Please enter name");
name = input.next();
System.out.println("Please enter age");
age = input.nextInt();
// only add the name and age to the arraylists if the age entered is greater
// than zero(0)
if (age > 0) {
names.add(name);
ages.add(age);
} else {
// break out of the loop if the user enters a value of zero(0) for age
break;
}
}
// You might want to print out the names and ages
System.out.println(names.toString());
System.out.println(ages.toString());
// Get and display the average age, oldest person and youngest person
getAverageAge(ages);
getNameOfOldest(ages, names);
getNameOfYoungest(ages, names);
}
// Method to get the name of the oldest person
public static void getNameOfOldest(ArrayList<Integer> ages, ArrayList<String> names) {
// Store the first value in the ages arraylist temporarily
// Also store the corresponding index of the first value which is zero
// Don't forget, arraylists are indexed from zero.
int temp = ages.get(0);
int index = 0;
// Now start loop at 1,
// since the first element (at zero(0)) has been stored temporarily in variable
// temp above.
// Loop through the arraylist and get the index of the smallest element
// in the ages arraylist.
for (int i = 1; i < ages.size(); i++) {
if (ages.get(i) > temp) {
temp = ages.get(i);
index = i;
}
}
// Using the index of the biggest element, get the corresponding name from the
// names arraylist
System.out.println("Name of oldest is " + names.get(index));
}
// Method to get the name of the youngest person
public static void getNameOfYoungest(ArrayList<Integer> ages, ArrayList<String> names) {
// Store the first value in the ages arraylist temporarily
// Also store the corresponding index of the first value which is zero
// Don't forget, arraylists are indexed from zero.
int temp = ages.get(0);
int index = 0;
// Now start loop at 1,
// since the first element (at zero(0)) has been stored temporarily in variable
// temp above.
// Loop through the arraylist and get the index of the smallest element
// in the ages arraylist.
for (int i = 1; i < ages.size(); i++) {
if (ages.get(i) < temp) {
temp = ages.get(i);
index = i;
}
}
// Using the index of the smallest element, get the corresponding name from the
// names arraylist
System.out.println("Name of youngest is " + names.get(index));
}
public static void getAverageAge(ArrayList<Integer> ages) {
// Initialize sum to zero.
int sum = 0;
// Using enhanced for loop, find the sum of elements in the ages arraylist
for (int age : ages) {
sum += age;
}
// Using the result of sum, divide by the length or size of the arraylist
// to get the average
double average = (double) sum / ages.size();
System.out.println("The average age is " + average);
}
}
Explanation:
Explanation has been given in the code as comments. You might want to get the source code attached to this answer for more readability. File is saved as "AgeStatistics.java"
Hope this helps!
