pls explain about time() and how it work?

Question

#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;

int main () {
srand(time(0));
for (int x = 1; x <= 10; x++) {
cout << 1 + (rand() % 6) << endl;
}
} pls explain about this program's functionality.