Найти количество делителей двух чисел

#include <cstdio>
 
unsigned gcd(unsigned a, unsigned b)
{
  if (!a || !b) return a + b;
  while (a != b) if (a > b) a -= b; else b -= a;
  return a; 
}
 
unsigned pairs_count(unsigned n)
{
  unsigned total = 0;
  for (unsigned a = 1; a * a <= n; a++)
    for (unsigned b = a + 1; a * b <= n; b++)
      if (!(n % a) && !(n % b) && gcd(a, b) == 1) 
        total++, printf("# %u ≥ %u * %u\n", n, a, b);
  return total;  
}
 
int main()
{
  unsigned n = 0;
  do printf("\n? n = ");
  while (scanf("%u", &n) != 1 || !n);
  printf("$ Всего пар: %u\n", pairs_count(n));
  return 0;
}

unsigned gcd(unsigned a, unsigned b)
{
  if (!a || !b) return a + b;
  while ((a + b) != 0) if (a > b) a %= b; else b %= a;
  return a; 
}

unsigned gcd (unsigned a, unsigned b) 
{
    while (b != 0) {
        a %= b;
        std::swap(a, b);
    }
    return a;
}

unsigned pairs_count(unsigned n)
{
  unsigned total = 0;
  for (unsigned a = 1; a * a <= n; a++)
    if (n%a) continue;
    for (unsigned b = a + 1;  b <= n/a; b++)
      if (!(n % b) && gcd(a, b) == 1) 
        total++, printf("# %u ≥ %u * %u\n", n, a, b);
  return total;  
 
}

#include <cstdio>
#include <cstdlib>
#include <ctime>
 
unsigned gcd(unsigned a, unsigned b)
{
  if (!a || !b) return a + b;
  while (a != b) if (a > b) a -= b; else b -= a;
  return a; 
}
 
unsigned pairs_count(unsigned n, clock_t &duration)
{
  unsigned total = 0;
  duration = clock();
  
  for (unsigned a = 1; a * a <= n; a++)
    for (unsigned b = a + 1; a * b <= n; b++)
      if (!(n % a) && !(n % b) && gcd(a, b) == 1) 
        total++;//, printf("# %u ≥ %u * %u\n", n, a, b);
        
  duration = clock() - duration;       
  return total;  
}
 
int main()
{
  system("chcp 65001 && cls");
  unsigned n = 0;
  
  
  do printf("\n? n = ");
  while (scanf("%u", &n) != 1 || !n);
  
  clock_t t;
  printf("$ Всего пар: %u\n", pairs_count(n, t));
  printf("$ Время: %lu мс\n", t);
  return 0;
}

unsigned pairs_count(unsigned n)
{
  unsigned total = 0;
  for (unsigned a = 1; a * a <= n; a++) {
    if (n%a) continue;
    for (unsigned b = a + 1;  b <= n/a; b++)
      if (!(n % b) && gcd(a, b) == 1) 
        total++, printf("# %u ≥ %u * %u\n", n, a, b);
  }
  return total;  
 
}

unsigned pairs_count(unsigned n, clock_t &duration)
{
  unsigned total = 0;
  duration = clock();
  
  for (unsigned a = 1; a * a <= n; a++)
    if (!(n % a)) // модификация (© Байт)
      for (unsigned b = a + 1; a * b <= n; b++)
        if (/*!(n % a) &&*/ !(n % b) && gcd(a, b) == 1) 
          total++;//, printf("# %u ≥ %u * %u\n", n, a, b);
        
  duration = clock() - duration;       
  return total;  
}

#include <iostream>
#include <vector>
#include <algorithm>
 
using namespace std;
 
int gcd(int a, int b)
{
    int tmp;
    while(b != 0)
    {
        tmp=a%b;
        a=b;
        b=tmp;
    }
    return a;
}
 
int main()
{
    vector<int> factors;
    int n,k,sz,a,b,c;
 
    cout << "n=";
    cin >> n;
    
    k=2;
    while (k*k<=n)
    {
        if (n%k==0)
        {
            factors.push_back(k);
            if (n/k != k) factors.push_back(n/k);
        }
        k++;
    }
    
    sort(begin(factors), std::end(factors));
 
    sz=factors.size();
    c=0;
    
    for (int i=0; i<sz-1; i++)
        for (int j=i+1; j<sz; j++)
        {
            a=factors[i];
            b=factors[j];
            if ((gcd(a,b)==1) && (a*b<n)) 
            {
                cout << a << " " << b << endl;
                c++;
            }
        }    
    
    cout << "c=" << c;
 
    return 0;
}