Sieve of Eratosthenes algorithm

I have no idea whether it is more efficient or not, but I watched https://youtu.be/V08g_lkKj6Q?si=QE9cdUNjvRBZh44n and implemented the below code.

 /*[13] Create a program to find all the prime numbers between 1 and 100. There is a classic method for doing this, called the “Sieve of Eratosthenes.” If you don’t know that method, get on the Web and look it up. Write your program using this method.*/

// This program finds all prime numbers between 1 and 100 using the Sieve of Eratosthenes method.

#include "PPP.h";

int main()
{
    vector<int> number_sequence;

    // generates sequence of numbers from 0 to 100:
    for (int i = 0; i <= 100; ++i)          // starts from 0 to make indexing easier
        number_sequence.push_back(i);

    // Seive of Eratosthenes method for calculating prime numbers between 1 and 100:
    number_sequence[1] = 0;                 // 1 is not a prime 

    for (int i = 2; i * i <= 100; ++i)      // starts from 2, as 0 and 1 are not prime numbers
        if (number_sequence[i] != 0)
            for (int j = i * 2; j < number_sequence.size(); j += number_sequence[i])
                number_sequence[j] = 0;     // make the number as 0 if the number is not a prime
     
    // outputs prime numbers:
    for (int x : number_sequence)
        if (x != 0)                         // since the non prime nubers are marked as 0 we exclude
            cout << x << " ";
    cout << '\n';
}