Question

Write a program that asks the user for an integer and then prints out all its factors. For example, when the user enters 84, the program should print 2 2 3 7 Validate the input to make sure that it is not a character or a string using do loop.in c++

Answer 1

#include<iostream>
#include<limits>
using namespace std;
void printFactors(int n)
{
//printing all factors of n
while (n % 2 == 0)
{
cout << 2 << " ";
n = n/2;
}
for (int i = 3; i*i <= n; i = i + 2)
{
while (n % i == 0)
{
cout << i << " ";
n = n/i;
}
}
if (n > 2)
cout << n << " ";
}

int main()
{
   //reading input and validating it
   int n;
   do{
   cout<<"Enter a number:";
   cin>>n;
   if(!cin.fail())
   break;
   else
   cin.clear();
   cin.ignore(numeric_limits<streamsize>::max(),'\n');
   cout<<"Enter number only\n";
   }
   while(1);
   printFactors(n);
   cout<<endl;
   return 0;
}

output:

Enter a number:s
Enter number only
Enter a number:84
2 2 3 7

Process exited normally.
Press any key to continue . . .