Question

Assume you are to write a ledger program that keeps track of each bank transaction as a struct containing the transaction type (deposit or withdrawal), the transaction amount (double), and the balance after the transaction. Would you use an array or a linked list? Why? (in C++)

Answer 1

Dear Student,

Thanks for posting an interesting question to decide between array or linked list to keep track of each bank transaction.

1. Answer in short. Linked List.

2. Why? Because to declare and initialize the array we must need to give the size of the array. The problem with the size of the array is explained with the below example:-

For example, Let's suppose I took the size of the array as 1000. After inserting 1000 transaction into the array when we will try to store 1001th transaction then we will get Segmentation fault for the 1001th transaction as the memory was not allocated for the 1001th transaction while creating the array. Hence, we will run into the problem if our no of transactions crossed the upper limit of 1000. So, to overcome this issue we generally use Linked List data strcuture because it is not fixed in size and is a example of dynamic storage of information.

3. In linked list we use node which is having one data part to store the information and the links to point the next node. So for the given question, I have created on structure with the given fields. Two methods are created in the below example. One method for inserting node and second method to display the information present in the linked list. Complete C++ program for linked list implementation to track transactions is mentioned below with proper comments:-

#include<iostream> using namespace std; //Declaring enum to store only two values either deposit or withdrawal enum TRANSACTION_TYPE {Deposit, Withdrawal); von WHO OWN Енн ннннн //Node type structure Estruct Node{ //Transaction type variable TRANSACTION_TYPE transactionType; //double transactionAmount double transactionAmount; //double balance double balance; //Node type variable to hold the next node Node *next; }; Η Η 20 //Node type variable head to hold the first node of the linked list Node *head=NULL; Ν Ν 23 //Below method will insert the node newNode into the linked list 24 Qvoid insertNode (Node *newNode) { 25 //Node type temp variable Node *temp; 27

//If head is null it means that this is the first node going to insert into the linked list //In other words it is a first transaction so head will point to the newNode if(head==NULL) head=newNode; else{ //Otherwise store the head in temp temp=head; //Iterate till we find last node while (temp->next != NULL) temp = temp->next; //store the next node to the newNode temp->next=newNode; w www ь Ф Ф Ф Ф Фu оноо со 10 л во нор со ослоороо со ы р д л а л ол Слл //Below method will display the linked list till the end with each value of the node Evoid display() { Node *temp; temp=head; while (temp !=NULL) { if(temp->transactionType==0) { cout<<"Deposit"; }else{ cout<<"Withdrawal"; cout<<" amount is: "<<temp->transactionAmount<<" and balance is: "<<temp->balance;

л | un cout<<"\n"; temp = temp->next; л o л и co //Main method Fint main() { Node *newNode; //Below statement will create five nodes and its properties //then inserting all the nodes into the linked list newNode=new Node; newNode->transactionType-Deposit; newNode->transactionAmount=5000.00; newNode->balance=50000.50; newNode->next=NULL; insertNode (newNode); newNode=new Node; newNode->transactionType-withdrawal; newNode->transactionAmount=2000.00; newNode->balance=20000.05; newNode->next=NULL; insertNode (newNode); newNode=new Node;

newNode->transactionType-Deposit; newNode->transactionAmount=500.00; newNode->balance=28000.00; newNode->next=NULL; insertNode (newNode); newNode=new Node; newNode->transactionType=Deposit; newNode->transactionAmount-1600.00; newNode->balance=21458.00; newNode->next=NULL; insertNode (newNode); newNode=new Node; newNode->transactionType=Deposit; newNode->transactionAmount=2000.00; newNode->balance=70000; newNode->next=NULL; insertNode (newNode); 100 101 102 103 104 //Displaying the linked list display();

4. Complete program in text format with proper comments is mentioned below for ready copying:-

#include<iostream>

using namespace std;

//Declaring enum to store only two values either deposit or withdrawal
enum TRANSACTION_TYPE {Deposit, Withdrawal};

//Node type structure
struct Node{
   //Transaction type variable
   TRANSACTION_TYPE transactionType;
   //double transactionAmount
   double transactionAmount;
   //double balance
   double balance;
   //Node type variable to hold the next node
   Node *next;
};

//Node type variable head to hold the first node of the linked list
Node *head=NULL;

//Below method will insert the node newNode into the linked list
void insertNode(Node *newNode){
  
   //Node type temp variable
   Node *temp;
  
   //If head is null it means that this is the first node going to insert into the linked list
   //In other words it is a first transaction so head will point to the newNode
   if(head==NULL)
           head=newNode;
   else{//Otherwise store the head in temp
       temp=head;
       //Iterate till we find last node
       while (temp->next != NULL)
           temp = temp->next;
           //Store the next node to the newNode
           temp->next=newNode;
   }
}

//Below method will display the linked list till the end with each value of the node
void display(){
Node *temp;
temp=head;

while (temp!=NULL) {
   if(temp->transactionType==0){
       cout<<"Deposit";
   }else{
       cout<<"Withdrawal";
   }
cout<<" amount is: "<<temp->transactionAmount<<" and balance is: "<<temp->balance;
   cout<<"\n";
temp = temp->next;
}
}

//Main method
int main(){
  
   Node *newNode;
  
   //Below statement will create five nodes and its properties
   //then inserting all the nodes into the linked list
   newNode=new Node;
   newNode->transactionType=Deposit;
   newNode->transactionAmount=5000.00;
   newNode->balance=50000.50;
   newNode->next=NULL;
   insertNode(newNode);
  
   newNode=new Node;
   newNode->transactionType=Withdrawal;
   newNode->transactionAmount=2000.00;
   newNode->balance=20000.05;
   newNode->next=NULL;
   insertNode(newNode);
  
   newNode=new Node;
   newNode->transactionType=Deposit;
   newNode->transactionAmount=500.00;
   newNode->balance=28000.00;
   newNode->next=NULL;
   insertNode(newNode);
  
   newNode=new Node;
   newNode->transactionType=Deposit;
   newNode->transactionAmount=1600.00;
   newNode->balance=21458.00;
   newNode->next=NULL;
   insertNode(newNode);
  
   newNode=new Node;
   newNode->transactionType=Deposit;
   newNode->transactionAmount=2000.00;
   newNode->balance=70000;
   newNode->next=NULL;
   insertNode(newNode);  
  
   //Displaying the linked list
   display();
}      

5. Please find below output of the program after executing it. Please note that I have saved the file with transactionll at D:/.

C. C:\Windows\system32\cmd.exe D:\>g++ transactionll.cpp D:\a.exe Deposit amount is: 5000 and balance is: 50000.5 Withdrawal amount is: 2000 and balance is: 20000 Deposit amount is: 500 and balance is : 28000 Deposit amount is: 1600 and balance is : 21458 Deposit amount is: 2000 and balance is : 70000 D:\>

6. i) Please note that inside the main method you can call as many as insertNode method as you want to store the transaction information in the given linked list example.

ii) The above program is just a demo to explain the motive which is good array or linked list. Actual requirement may differ from the above example. Important part of the code I marked in bold.

7. Though I put comments to each of the line of the code and tried to explain easily. Still, if you have any query please feel free to reach me through comments section. I will be more than happy to help you further.

8. Please upvote if you liked my answer.

Thanks!!

Happy Learning!!