Write a C++ program to display Pascal’s triangle using the friend function.

Write a C++ program to display Pascal’s triangle using the friend function.

If we declare a function friend int show(T4Tutorials);  as a friend in a class T4Tutorials then this function friend int show(T4Tutorials);  can access the private and protected members of the class T4Tutorials. You must know that a global function can also be declared as a  friend function of the class.

Syntax of friend function in C++

class class_name
{
…
friend return_type function_name(arguments);
…
}

#include<iostream>
using namespace std;
class T4Tutorials
{
public:
int r,s,i,j,c;
public:
	int pattern()
	{
		cout<<"Enter number of rows"<<endl;
		cin>>r;
	}
	friend int show(T4Tutorials);
};

int show(T4Tutorials a)
{
	for(a.i=0;a.i<a.r;a.i++)
				{
					for(a.s=1;a.s<=a.r-a.i;a.s++)
					{
						cout<<" ";
					}
					for(a.j=0;a.j<=a.i;a.j++)
					{
						if(a.j==0||a.i==0)
						{
							a.c=1;
						}
						else
						{
							a.c=a.c*(a.i-a.j+1)/a.j;
						}
						cout<<a.c<<" ";
					}
					cout<<endl;
				}
}
int main()
{
	T4Tutorials a;
	a.pattern();
	show(a);
}

Output