prime factorization

[Bill2345]

I have a question for prime factorization since I am being asked to validate the input to exclude anything that is a string, character, or a negative number using a do loop

#include <iostream>
using namespace std;

int main()
{
int a;
int n;
do
{
n % 2==0;

[mbozzi]

Something like this, maybe:

#include <string>
#include <string_view>
#include <cstdlib>
#include <iostream>

bool parse_number(std::string_view s, long long& n)
{
  char*       parse_end = nullptr;
  char const* s_begin   = s.data();
  char const* s_end     = s.data() + s.size();

  n = std::strtoll(s_begin, &parse_end, 10);

  return (parse_end == s_end) && (s.size());
}

int main()
{
  std::string s; 
  long long n = 0;

  std::cin.exceptions(~std::ios_base::goodbit);
  do std::cin >> s; while (!(parse_number(s, n) && n >= 0));
  
  std::cout << n << '\n';
}

Save parse_number, you'll use it again.

[Bill2345]

The problem states "Write a program that asks the user for an integer and then prints out all its prime factors. For example, when the user 84 the program should print
2
2
3
7
Validate the input to make sure that it is not a character or a string or a negative number using a do loop
The program I use is Dev C++ 6.3

[mbozzi]

You're not entitled to my help.

[jonnin]

read it in as a string, see if it is a number .. for positive values, its just isdigit for all of them since no decimal, minus sign, or other junk would be allowed. then factor it if valid.