Could someone help me with code optimization?

[ralf102]

I've made a program that show number as a product of it's prime numbers. Unfortunately it's too slow with big numbers. Could you help me optimize it?

  #include <iostream>
using namespace std;
int main()
{
int liczba;
while (cin >> liczba){

int l,b;
l=b;
for (int i=2; i <= liczba; i++)
{
 while(liczba % i == 0)
 {
   liczba /= i;
   l=l/i;
   cout <<  i;
   if (liczba>1)
    cout <<"*";
   }
}
cout <<endl;
}
}

[ne555]

> for (int i=2; i <= liczba; i++)
Consider to test only the primes number that are less or equal than sqrt(liczba)

for(auto p: prime_list){
   if(p*p > liczba) break;
   //factorize
}