Why do we use srand()?

Question

https://code.sololearn.com/c9NJ4GbiWsWj/?ref=app

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

int main()
{
//define the range
int from = 8;
int to = 42;

srand(time(0));
cout << from + (rand() % (to - from + 1));

return 0;
}

Here SoloLearn used srand function but later using rand function, then why I needed to call srand function??

And why we need to subtract a variable from another??

Answer 1

Jazz Thanks Jazz!!