Question

Write a program the declares and uses two parallel arrays. One array for storing the names of countries and a second array for storing the populations of those countries. As you can see per the following the Country name and it's corresponding Population are stored at the same element index in each array.

China	1367960000
India	1262670000
United States	319111000
Indonesia	252164800
Brazil	203462000
Pakistan	188172000
Nigeria	178517000
Bangladesh	157339000
Russia	146149200
Japan	127090000

In the main method write a loop which asks the user if they would like to look up a given country's population.  

• If No, then terminate the program
• If Yes,
  • Call a value returning method, no parameters required:
    • This method prompts the user: What country would you like to look up?
    • The value entered is returned from this method
  • Call a second value returning method, passing it the value returned from the previous method call (ie. The name of the Country being searched for)
    • This method searches the country names array to see if it's there.
    • If it is there (ie it's found), return the population corresponding to the country
    • If it is NOT there, return a -1 which indicates the country was not found in the Country array
  • Back in the main method output the Country name searched for and it's population if found or Not Found when Not Found

i.e,

public class InClassModule_9 {

        public static String[] country = {"China", "India", "United States", "Indonesia", "Brazil", 
            "Pakistan", "Nigeria", "Bangladesh", "Russia", "Japan"};
        
        public static int[] population = {1367960000, 1262670000, 319111000, 252164800, 203462000, 
                        188172000, 178517000, 157339000, 146149200, 127090000};

        public static void main(String[] args) {

                System.out.println("Output/display contents from both arrays");
                for(int x=0; x < country.length; x++) {
                        System.out.println(x + ") Country: " + country[x] + "\tPopulation: " + population[x]);
                }
                System.out.println("\nThe End!!");

        }

}

Answer 1

Here is your solution

I create two methods

public String askUser()  //this is use for ask country name to user

public int findPop(String n)  //this is use to find population on given country name

Code:

import java.util.*;

public class InClassModule_9 {
        
        //use for taking input from user
        static Scanner sc = new Scanner(System.in);
        
        public static String[] country = {"China", "India", "UnitedStates", "Indonesia", "Brazil", 
            "Pakistan", "Nigeria", "Bangladesh", "Russia", "Japan"};
        
        public static int[] population = {1367960000, 1262670000, 319111000, 252164800, 203462000, 
                        188172000, 178517000, 157339000, 146149200, 127090000};
        
        //method with no parameters and return value(country name)
        public String askUser(){
  
            System.out.print("What country would you like to look up? : ");
            //scan and return
            return sc.next();
        }
        
        //method with parameters and return value(population)
        public int findPop(String n){
            
            for(int x=0; x < country.length; x++) {
                //if country name match then it will return 
                    if(country[x].toLowerCase().equals(n.toLowerCase())){
                        //return population of the country
                        return population[x];
                    }
                }
           //return if country not found
            return -1;
        }
        
        public static void main(String[] args) {
            //flag for user choice     
            String flag;
                
                //display all countries and population 
                for(int x=0; x < country.length; x++) {
                        System.out.println(x + ") Country: " + country[x] + "\tPopulation: " + population[x]);
                }
                
                //creating object for calling methods
                InClassModule_9 obj = new InClassModule_9();
                
                //ask user 
                System.out.print("\nwould you like to look up a given country's population? (Yes/No) : ");
                flag = sc.next();
                
                /*here i convert user input into lowercase and then match with "yes"
                    "yes" & "YES" both are same*/
                while(flag.toLowerCase().equals("yes")){
                    //first method call
                    String c = obj.askUser();
                    //second method call
                    int p = obj.findPop(c);
                    
                    //check return output and print according to that
                    if( p != -1){
                        System.out.println(c+" : "+p);
                    }else{
                        System.out.println("Not Found");
                    }
                    
                    //ask user 
                    System.out.print("\nwould you like to look up a given country's population? : ");
                    flag = sc.next();
                }
                
            System.out.println("\nThe End!!");
        }

}

Output:

I hope this solution will help you.

If you have any doubts about this, then do comment below.

Do you feel it is helpful to you?

Then please up vote me.  

Thank You :)