Answer to Question #156131 in C++ for Adiba

Question

We would like to implement the abstract data type called “Bag” that keeps track of bag of blobs. A bag has a maximum size Msize and supports insert, delete, IsEmpty, IsFull, and constructor/destructor operations.

Insert adds a new blob to the bag and Delete removes a blob from the bag. Assume blob is a record type. A bag of blobs can be implemented using an array A[1..Msize] of blob pointers. If there are k blobs in the bag then the entries A[1], ..., A[k] point to these blobs. The remaining entries of the array point to null.

Answer 1

#include <iostream>
#include <string>
using namespace std;
const int Msize = 10; //You can set it according to your requirement
typedef struct {
    int where;
    string other;
    
} Blob;
class Bag {
    Blob *b[Msize]; 
    public:
    //constructor
    Bag () {
        for (int i = 0; i < Msize; i++)
            b[i] = NULL;
    }
    //isEmpty function: returns true or false whether bag is empty or not
    bool isEmpty () {
        for (int i = 0; i < Msize; i++)
            if (b[i] != NULL) return false;
        return true;
    }
    //isFull function:returns true or false whether bag is empty or not
    bool isFull () {
        for (int i = 0; i < Msize; i++)
            if (b[i] == NULL) return false;
        return true;
    }
    //to insert a new blob in the bag
    bool insert (Blob blb) {
        /* if the bag is full or the position is already occupied it will not insert*/
        if (b[blb.where] != NULL or isFull()) return false;
        b[blb.where] = &blb; //else it will insert the blob
        return true;
    }
    //to delete a blob from the bag
    bool del (Blob blb) {
        /*If blob is not present or the bag is empty it will return false*/
        if (b[blb.where] == NULL or isEmpty()) return false;
        b[blb.where] = NULL; //else it will delete the blob
        return true;
    }
    //to print the contents of the bag
    void print () {
        cout << "[ ";
        for (int i = 0; i < Msize; i++) 
            cout << (b[i] == NULL ? "null" : to_string (b[i]->where)) << " ";
        cout << "]\n";
    }
    //to count the no_of_blob in the bag
    int no_of_blob()
    {
        int count=0;
        for (int i = 0; i < Msize; i++)
            if (b[i] != NULL) count++; //if blob is not null then increment the count
            return count;
    }
};
//main function to test the code
int main()
{
    //inserting 3 blobs in the bag
    Blob first, third, fourth;
    first.where = 1; first.other = "First";
    third.where = 3; third.other = "Third";
    fourth.where = 4; fourth.other = "Fourth";
    Bag myBag;
    cout<<"Initial bag: ";
    myBag.print();
    myBag.insert (first);
    myBag.insert (third);
    myBag.insert (fourth);
    cout<<"Bag after insert:";
    myBag.print();
    cout<<"Total Blob: "<<myBag.no_of_blob()<<endl;
    //now delete blobs
    myBag.del (third);
    myBag.del(first);
    cout<<"Bag after delete";
    myBag.print();
    cout<<"Total Blob: "<<myBag.no_of_blob()<<endl;
    return 0;
}