How to Make readNo method Private - c++

Question

here is my code. wriiten for to to find armstrong, factorial etc. now i want readNo method private what should i do..?
#include<iostream.h>
#include<stdio.h>
#include<conio.h>
class Num_Demo
{
public:
int num;
void readNo(int no)
{
num=no;
}
int Factorial (int a)
{
if(a!=0)
{
int f=1;
for (int i=1;i<=a;i++)
{
f=f*i;
}
return f;
}
else
{
return 0;
}
}
int Reverse(int b)
{
int rev=0,rem;
while(b!=0)
{
rem=b%10;
rev=(rev*10)+rem;
b=b/10;
}
return rev;
}
void Palindrome (int c)
{
int num;
int rev=0,rem;
num=c;
while(c!=0)
{
rem=c%10;
rev=(rev*10)+rem;
c=c/10;
}
if(num==rev)
{
cout<<" Number Is Palindrome";
}
else
cout<<" Number is Not Plaindrome";
}
void Armstrong (int d)
{
int sum=0,n1,copy;
copy=d;
while(d!=0)
{
n1=d%10;
sum=sum+n1*n1*n1;
d=d/10;
}
if(sum==copy)
{
cout<<" Number Is Armstrong";
}
else
cout<<" Number is Not Armstrong";
}
};
int main()
{ clrscr();
Num_Demo nd1,nd2,nd3,nd4;
int n1,n2,n3,n4;
cout<<"\n\nEnter The Number To Find Factorial\t";
cin>>n1;
nd1.readNo(n1);
cout<<" The Factorial Is\t"<<nd1.Factorial(n1);
cout<<"\n\nEnter The Number To Find Reverse Number\t";
cin>>n2;
nd2.readNo(n2);
cout<<" The Reverse Is\t"<<nd2.Reverse(n2);
cout<<"\n\nEnter The Number To Find Palindrome\t";
cin>>n3;
nd3.readNo(n3);
nd3.Palindrome(n3);
cout<<"\n\nEnter The Number To Find Armstrong\t";
cin>>n4;
nd4.readNo(n4);
nd3.Armstrong(n4);
getch();
return 0;
}
now i want to make readNo method private. what should i do..? whent i place readNo outside public error "readNo not accessible" pop up. please help me.

Answer 1

You don't use a private function in main function. It's unacceptably.

Answer 2

You put function under private: tag in class definition, but then you can't call it outside from your class, soo then you need public function which will call private function in class.