How to find the Factorial and Sum of Series Number using Recursion in c++

 Implementation of Recursion

 #include<iostream>//headerfile
using namespace std;//for std
#define size 5//fixed size
struct Stack{ //to make stack
	int arr[size];
	int top = -1;
	bool isEmpty()//to check stack is this empty
	{
		return (top < 0);
	}
	bool isFull()//to check stack is this full
	{
		return (top == size - 1);
	}
	void push(int n) //to push the value and store it into the stack
	{
		if (isFull())
		{
			cout << "Stack is Full" << endl;
		}
		else
		{
			arr[++top] = n;

		}
	}
	int pop()//to remove the value from stack
	{
		if (isEmpty())
		{
			cout << "There is nothing to show" << endl;
		}
		else
		{
			int a = arr[top--];
			return a;
		}
	}
	int peek()//to remove or check the top of the stack
	{
		if (isEmpty())
		{
			cout << "There is noting to show" << endl;
		}
		else
		{
			int a = arr[top];
			return a;
		}
	}
	int sum(int n)//Recusrive function to make sum
	{
		if (n <= 1)
		{
			return 1;
		}
		else
		{
			return n + sum(n - 1);
		}
	}
	int fact(int n)//Recusrive function to take factorial
	{
		if (n <= 1)
		{
			return 1;
		}
		else
		{
			return n * fact(n - 1);
		}
	}
};
int main()
{
	Stack s1;
	int x = 10;
	s1.push(s1.sum(x));
	s1.push(s1.fact(x));
	int a = s1.pop();
	cout <<"Factorial is:"<< a << endl;
	a = s1.pop();
	cout << "Sum of the series is:" << a << endl;
	getchar();
	getchar();
	return 0;
}