Question

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Write the class, GeoLocation.java. You can refer to Name.java used in the lecture to complete the below exercises. Do the following: 1. Create two instance variables, lat and lng, both of which should be doubles. 2. Write the default constructor. 3. Write the non-default constructor. 4. Write 2 accessor methods, one for each instance variable. 5. Write 2 mutator methods, one for each instance variable. 6. Write a method that will return the location in the format "(lat, lng)" (the toString method). 7. Write a method that will return true if the latitude is between -90 and +90. 8. Write a method that will return true if the longitude is between -180 and +180. 9. Optional: Write a method that will take a String in the format "(lat, lng)" and return a GeoLocation. 10. Now write an application class that instantiates two instances of GeoLocation. One instance should use the default constructor and the other should use the non-default constructor. Display the values of the instance variables by calling the accessor methods.

Answer 1

Create a file named GeoLocation.java and paste the below code in it

CODE:

public class GeoLocation {
   private double lat;
   private double lng;
  
   //Default constructor. It means it takes no arguments.
   //if we didn't create this constructor explicitly.then by default java creates default constructor.
   GeoLocation() {
       super();
   }
  
   //non-default constructor which takes lat and lng as arguments.
   public GeoLocation(double lat, double lng) {
       super();
       this.lat = lat;
       this.lng = lng;
   }

   //accessor method for lat
   public double getLat() {
       return lat;
   }
   //mutator method for lat
   public void setLat(double lat) {
       this.lat = lat;
   }
  
   //accessor method for lng
   public double getLng() {
       return lng;
   }
  
   //mutator method for lng
   public void setLng(double lng) {
       this.lng = lng;
   }
  
   //toString() method . It is used to print the object in desirec format
   @Override
   public String toString() {
       return "("+lat + "," + lng + ")";
   }
  
   //checks lat whether it is between -90 and 90.8 and return true it it is.
   public boolean checkLat()
   {
       if(this.lat>=-90 && this.lat<=90.8)
           return true;
       return false;
   }
  
   //checks lng whether it is between -180 and 180.9 and return true it it is.
   public boolean checkLong()
   {
       if(this.lng>=-180 && this.lng<=180.9)
           return true;
       return false;
   }
   //optional method
   public GeoLocation getGeoLocation(String coordinates)
   {
       String[] latlng=coordinates.split(","); //splitting string to get lat and lng
       String strlat=latlng[0].substring(1); //getting lat
       double lat=Double.parseDouble(strlat); //converting lat from string to double
       String strlng=latlng[1].substring(1); //getting lng
       double lng=Double.parseDouble(strlng); //converting lat from string to double
       GeoLocation geoLocation=new GeoLocation(lat,lng); //creating GeoLocation object
       return geoLocation; //returning object
      
   }
  

}

Create a file name application.java and paste the below code in it.

CODE:

public class application
{
  
   public static void main(String[] args)
   {
       //Creating object using default constructor
       GeoLocation location1=new GeoLocation();
       location1.setLat(108.9); //setting values using mutator method
       location1.setLng(90.7); //setting value using mutator method
      
       //Hardcoding values of lat and lng to create new GeoLocation object
       double lat=78.5;
       double lng=56.7;
      
       //Creating object using non-default constructor
       GeoLocation location2=new GeoLocation(lat,lng);
      
       System.out.println("Location 1:");
      
       System.out.println("Lat:"+location1.getLat()); //printing values using accessor method
       System.out.println("Lng:"+location1.getLng()); //printing values using accessor method
      
       System.out.println("\nLocation 2:");
      
       System.out.println("Lat:"+location2.getLat()); //printing values using accessor method
       System.out.println("Lng:"+location2.getLng()); //printing values using accessor method
      
   }
}

OUTPUT:

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