Polymorphic billing
Medium
Java
OOP Basics
17 views
Problem Statement
Task: create interface Billable and two implementations. Return total bill for array of Billable.
Input Format
An array of Billable objects
Output Format
Total bill amount (sum of all items)
Example
Item1 bill = 100 Item2 bill = 200
300
Constraints
• Must use interface
• At least two different implementations
• Total is sum of all bills
• At least two different implementations
• Total is sum of all bills
Concept Explanation
Billable interface defines a method like getBill().
Two different classes implement it (for example Product and Service).
We store them in a Billable array.
We call getBill() on each and add them.
Two different classes implement it (for example Product and Service).
We store them in a Billable array.
We call getBill() on each and add them.
Step-by-Step Explanation
1.Create interface Billable with method to return bill amount.
2.Create two classes implementing Billable.
3.Each class calculates its bill in its own way.
4.Create an array of Billable.
5.Initialize total = 0.
6.Loop through array:
• Call bill method for each object.
• Add result to total.
7.Return total.
2.Create two classes implementing Billable.
3.Each class calculates its bill in its own way.
4.Create an array of Billable.
5.Initialize total = 0.
6.Loop through array:
• Call bill method for each object.
• Add result to total.
7.Return total.
Concept Explanation
Billable interface defines a method like getBill().
Two different classes implement it (for example Product and Service).
We store them in a Billable array.
We call getBill() on each and add them.
Two different classes implement it (for example Product and Service).
We store them in a Billable array.
We call getBill() on each and add them.
Step-by-Step Explanation
1.Create interface Billable with method to return bill amount.
2.Create two classes implementing Billable.
3.Each class calculates its bill in its own way.
4.Create an array of Billable.
5.Initialize total = 0.
6.Loop through array:
• Call bill method for each object.
• Add result to total.
7.Return total.
2.Create two classes implementing Billable.
3.Each class calculates its bill in its own way.
4.Create an array of Billable.
5.Initialize total = 0.
6.Loop through array:
• Call bill method for each object.
• Add result to total.
7.Return total.
Input / Output Format
Input Format
An array of Billable objects
Output Format
Total bill amount (sum of all items)
Constraints
• Must use interface
• At least two different implementations
• Total is sum of all bills
• At least two different implementations
• Total is sum of all bills
Examples
Input:
Item1 bill = 100
Item2 bill = 200
Output:
300
Example Solution (Public)
static interface Billable{int bill();}static class Item implements Billable{final int price;Item(int p){price=p;}public int bill(){return price;}}static class Pack implements Billable{final int unit;final int qty;Pack(int u,int q){unit=u;qty=q;}public int bill(){return unit*qty;}}static int total(Billable[] a){int s=0;for(Billable b:a) s+=b.bill();return s;}
Official Solution Code
static interface Billable{int bill();}static class Item implements Billable{final int price;Item(int p){price=p;}public int bill(){return price;}}static class Pack implements Billable{final int unit;final int qty;Pack(int u,int q){unit=u;qty=q;}public int bill(){return unit*qty;}}static int total(Billable[] a){int s=0;for(Billable b:a) s+=b.bill();return s;}
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