doubt regarding int array

[hszforu]

what does an array contain when it is declared?
For example, when i declare an int array numbers like:
int[] numbers=new int[5];
now without intializing any values, i tried to print that array.So it showed me that all elements inside that array were 0.
Now if 0 means empty, then if i assign some random values to that arrays, and then i assign
say for eg, number[3]=0.
does this mean that that element is empty or it means that it is simply assigned 0 value.

[gerard4143]

Uninitialized arrays are bitwise zeroed..The values for a uninitialized int array are zero.

[hszforu]

Uninitialized arrays are bitwise zeroed..The values for a an uninitialized int array are zero.

then how can we make a particular element at index i of array,contain nothing.The reason i am asking this is because i am implementing an stack program using arrays.
There is no problem i n push operation , but when i perform the pop operation then how to delete the top element in an array, should i assign it 0 value.
but if i assign it a 0 value then i don't think that it will delete that element, so what should be my approach for this?

[Mitja Bonca]

int array cannot be empty. Empty is for string. Int can have only numbers. So when you initialize a new integer array all indexes set to zero This is 0 and not empty.

[hszforu]

int array cannot be empty. Empty is for string. Int can have only numbers. So when you initialize a new integer array all indexes set to zero This is 0 and not empty.

so, how can we perform the pop operation in an int array.
So should i assign 0 value to the remaining elements when i perform an pop operation.

[Mitja Bonca]

pop operation? What is that?

[hszforu]

pop operation? What is that?

push and pop opeartions of an stack.
Push opearation= insert elements in an stack array.
pop operation= remove the topmost element in an array.here is the code that runs if i assign 0 value to all the remaining elements.

using System;
class stack12
{
    int tos;
    int[] stack;
    public void assignsize(int size)
    {
        stack = new int[size];
        tos = 0;
    }
    public void push(int no)
    {
        if (tos == stack.Length)
        {
            Console.WriteLine("the stack is full");
            return;
        }
        stack[tos] = no;
        tos++;
    }
    public void pop()
    {
        if (tos == 0)
        {
            Console.WriteLine("the stack is empty");
            return;
        }
        for (int i = tos; i < stack.Length; i++)
            stack[i] = 0;
        tos--;
    }
    public void display()
    {
        Console.WriteLine("\nthe stack now contains");
        for (int i = 0; i < stack.Length; i++)
            Console.Write(" "+stack[i]);
    }
}
class stackdemo
{
    static void Main()
    {
        stack12 obj1 = new stack12();
        int size = 5;
        obj1.assignsize(size);
        obj1.push(3);
        obj1.display();
        obj1.push(5);
        obj1.display();
        obj1.push(8);
        obj1.display();
        obj1.push(6);
        obj1.display();
        obj1.push(9);
        obj1.display();
        obj1.push(1);
        obj1.display();
        obj1.pop();
        obj1.display();
        obj1.pop();
        obj1.display();
    }  
}

[Narue]

So should i assign 0 value to the remaining elements when i perform an pop operation.

Unnecessary. The tos field is what determines where the top of the stack is, and when you push to a spot that's previously been populated, just overwrite the value.

However, if you really did need an "empty" integer (which you don't in this case), you could store it as a nullable type.

[hszforu]

Unnecessary. The tos field is what determines where the top of the stack is, and when you push to a spot that's previously been populated, just overwrite the value.

However, if you really did need an "empty" integer (which you don't in this case), you could store it as a nullable type.

yes i know tos determines the top of stack and i want an empty integer but i am not able to make that element empty, that's why i assigned 0 values to remaining array. Could you tell me how to make any element empty using nullable type?

[Narue]

yes i know tos determines the top of stack and i want an empty integer but i am not able to make that element empty, that's why i assigned 0 values to remaining array. Could you tell me how to make any element empty using nullable type?

I don't think you understand. You don't need to make that element empty. I suspect you think you need to make it empty because of the display() method, which is wrong. You should be using tos instead of stack.Length:

public void display()
{
    Console.WriteLine("\nthe stack now contains");
    for (int i = 0; i < tos; i++)
        Console.Write(" "+stack[i]);
}

This way only the valid contents of the stack are printed. The lesson in this is to fix the real problem, not try to cover it up.

[hszforu]

I don't think you understand. You don't need to make that element empty. I suspect you think you need to make it empty because of the display() method, which is wrong. You should be using tos instead of stack.Length:

public void display()
{
    Console.WriteLine("\nthe stack now contains");
    for (int i = 0; i < tos; i++)
        Console.Write(" "+stack[i]);
}

This way only the valid contents of the stack are printed. The lesson in this is to fix the real problem, not try to cover it up.

ok i understood, thanks.