fibonacci numbers in c++

                                    #include<iostream>
using namespace std;
int main()
{
    int num,num1=0,num2=1,num3,i=0;
    cout<<"enter the number num"<<endl;
    cin>>num;
    for(i=1;i<=num;i++)
    {
        num3=num1+num2;
        num1=num2;
        num2=num3;
        cout<<num3<<endl;
    }

}

                                    #include <iostream>
using namespace std;

int main()
{
    int n, t1 = 0, t2 = 1, nextTerm = 0;

    cout << "Enter the number of terms: ";
    cin >> n;

    cout << "Fibonacci Series: ";

    for (int i = 1; i <= n; ++i)
    {
        // Prints the first two terms.
        if(i == 1)
        {
            cout << " " << t1;
            continue;
        }
        if(i == 2)
        {
            cout << t2 << " ";
            continue;
        }
        nextTerm = t1 + t2;
        t1 = t2;
        t2 = nextTerm;
        
        cout << nextTerm << " ";
    }
    return 0;
}

                                    #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;
}