Print out array values in pairs

[deputy]

Hello everyone.Proabably it's quite simple, but i'm kind a stuck with one thing my task is to make queue with pop and push functions and also have to display the queue/array, i have a default constructor with parameter which passes the arrays size. So the thing is i need to print out the array values by two which are inside brackets and they are separeted by comma, when the bracket closes it separetes another pair with semicolon.It would supposed to look like {1,2};{3,4};{5,6}.I would be very greatfull for every help.Thanks

#include <iostream>
#include <cstdlib>
using namespace std;

class FIFO
{
    private:
        int front; 
        int rear; 
        int *arr; 
        int SIZE; 

    public:
        FIFO(int capacity) 
        {
            front = -1; 
            rear = -1;
            SIZE = capacity;
        for(int i = 0; i < SIZE; i++)
            {
                    arr[i] = 0; 
            }
        }

        bool isEmpty() 
        {
            if(front == -1 && rear == -1) 
                return true;
            else
                return false;
        }

        bool isFull()
        {
            if(rear == SIZE-1)  
                return true;
            else
                return false;
        }

        void Push(int val) 
            {
            if(isFull())
            {
            cout<<"Queue is full"<<endl;
                return;
            }
        else if(isEmpty()) 
            {
            rear = front = 0; 
            arr[rear] = val;
            }
        else  
            {
            rear++;
            arr[rear] = val;
            }
            }

        int Pop()
        {
            int x;
            if(isEmpty()) 
            {
            cout<<"Queue is empty "<<endl;
                return 0;
            }
            else if(front == rear) 
            {
                x = arr[front]; 
                arr[front] = 0; 
                rear = -1;
                front = -1;
                    return x;
            }
            else 
            {
                x = arr[front];
                arr[front] = 0;
                front++; 
                    return x;
            }
            }

          void Display()
        {
            cout<<"All values in the queue are - "<<endl;
                for(int i = 0; i < SIZE; ++i)
                {
                    cout<<"{"<<arr[i]<<",};";
                }
            }
};

int main()
{
    FIFO f1(6); 
    int  value;
    char option; 
    do
    {
      cout<<"What operation do you want to perform? Select Option number."<<endl;
      cout<<"+. Push()" <<endl;
      cout<<"-. Pop()" <<endl;
      cout<<"*. Display()" <<endl;
      cout<<"$. Exit" <<endl<<endl;

    cin>>option;
    switch(option)
    {
   case '+':
        cout<<"Push operation \nEnter an item to push in the queue "<<endl;
         while (!(cin >> value))//
    {
        cout << "ERROR: a number must be entered: "; 
        cin.clear();
        cin.ignore(123, '\n'); 
    }
        f1.Push(value);
    break;
   case '-':
        cout<<"Pop Operation \nPoped value: "<<f1.Pop()<<endl;
    break;
   case '*':
        cout<<"Display function called - "<<endl;
        f1.Display();
    break;
   case '$':
        break;
   default:
        cout<<"Enter proper option number "<<endl;
    }
    }while(option != '$');
    return 0;
}

[anup30]

#include<iostream>
using namespace std;

int main()
{
	const int size=6;
	int ar[size] = {1,2,4,8,16,32};
	
	if(size%2==0)
	{
		for(int i=0; i<size; i++)
		{
			if(i%2==0)
			{
				cout << "{" << ar[i] << ",";				
			}
			else
			{
				cout << ar[i] << "};";
			}
		}
	}
					
}

output:

{1,2};{4,8};{16,32};

[againtry]

Another way:

#include<iostream>

int main()
{
	const int size=6;
	int ar[size] = {1,2,4,8,16,32};
	
	for(int i=0; i<size; i+= 2 )
	    std::cout << "{" << ar[i] << "," << ar[i+1] << "};";
}

[deputy]

Thank you guys.

[seeplus]

FIFO(int capacity) 
        {
            front = -1; 
            rear = -1;
            SIZE = capacity;
        for(int i = 0; i < SIZE; i++)
            {
                    arr[i] = 0; 
            }
        }

The constructor has a major problem - you're not allocating any memory for arr! Also, you need a destructor to free the allocated memory.

FIFO(int capacity) : front(-1), rear(-1), SIZE(capacity), arr(new int[capacity] {}) {}
~FIFO() {delete [] arr; }

Also, these can be simplified:

bool isEmpty() 
        {
            if(front == -1 && rear == -1) 
                return true;
            else
                return false;
        }

        bool isFull()
        {
            if(rear == SIZE-1)  
                return true;
            else
                return false;
        }

becomes:

bool isEmpty() {return front == -1 && rear == -1; }
bool isFull() {return rear == SIZE - 1; }

PS Shouldn't Display() just display the current values in the queue - and not the whole queue?

[anup30]

againtry's code...

#include<iostream>

int main()
{
	const int size=6;
	int ar[size] = {1,2,4,8,16,32};
	
	for(int i=0; i<size; i+= 2 )
	    std::cout << "{" << ar[i] << "," << ar[i+1] << "};";
}

...will try to print from out of allowed memory by ar[i+1] if size=odd number.