efficient way to use fibonacci sequence in c++ code example

Example: fibonacci sequence c++

#include <iostream>
using namespace std;

int main ()
{
    int num1, num2, num3, input; 
    num1 = 0;
    num2 = 1;
    cout << "How many nums in sequence do you want to see: "; 
    cin >> input; 
    cout << num1 << " " << num2 << " "; 

    for(int i = 2; i < input; i++) // runs through every element but first two 
    {
        num3 = num1 + num2; 
        cout << num3 << " "; 
        num1 = num2; 
        num2 = num3; 
    }
    
    return 0;
}