fibonacci in c 2b 2b

1#include <iostream>
2using namespace std;
3int main()
4{
5	int num = 1, pre_num = 0, sum, n;
6	do
7	{
8		cout << "Enter number of terms 'n'of Fibonacci series: ";
9		cin >> n;
10		cout << "Fibonacci series: ";
11		for (int i = 0; i < n; i++)
12		{
13			sum = num + pre_num;
14			pre_num = num;
15			num = sum;
16			cout << num << " ";
17		}
18	return 0;
19}

1#include <iostream>
2using namespace std;
3
4int main(){
5	int a{0},b{1},count{},c{};
6	cin >> count;
7	for (int i = 0; i < count; ++i)
8	{
9		cout << a << endl;
10		c = b;
11		b = a + b;
12		a = c;
13	}
14}

1#include <iostream>
2using namespace std;
3
4int main ()
5{
6    int num1, num2, num3, input; 
7    num1 = 0;
8    num2 = 1;
9    cout << "How many nums in sequence do you want to see: "; 
10    cin >> input; 
11    cout << num1 << " " << num2 << " "; 
12
13    for(int i = 2; i < input; i++) // runs through every element but first two 
14    {
15        num3 = num1 + num2; 
16        cout << num3 << " "; 
17        num1 = num2; 
18        num2 = num3; 
19    }
20    
21    return 0;
22}

1#include<iostream>
2using namespace std;
3int main()
4{
5    int num,num1=0,num2=1,num3,i=0;
6    cout<<"enter the number num"<<endl;
7    cin>>num;
8    for(i=1;i<=num;i++)
9    {
10        num3=num1+num2;
11        num1=num2;
12        num2=num3;
13        cout<<num3<<endl;
14    }
15
16}
17

1//dp ;Bottom up approach
2#include <iostream>
3
4using namespace std;
5int fib(int n)
6{
7    int fib[n+1];
8    fib[0]=0;
9    fib[1]=1;
10    for(int i=2;i<=n;i++)
11    {
12        fib[i]=fib[i-1]+fib[i-2];
13    }
14    return fib[n];
15}
16
17int main()
18{
19    int n;
20    cout<<"enter the value whose fibonaaci value you want to claculate:"<<endl;
21    cin>>n;
22    if(n<=1)
23    {
24        cout<<"fib is: "<<n<<endl;
25    }
26    else
27    {
28        cout<<"fib is: "<<fib(n)<<endl;
29    }
30    return 0;
31}
32

1#include <iostream>
2using namespace std;
3
4int main()
5{
6    int n, t1 = 0, t2 = 1, nextTerm = 0;
7
8    cout << "Enter the number of terms: ";
9    cin >> n;
10
11    cout << "Fibonacci Series: ";
12
13    for (int i = 1; i <= n; ++i)
14    {
15        // Prints the first two terms.
16        if(i == 1)
17        {
18            cout << " " << t1;
19            continue;
20        }
21        if(i == 2)
22        {
23            cout << t2 << " ";
24            continue;
25        }
26        nextTerm = t1 + t2;
27        t1 = t2;
28        t2 = nextTerm;
29        
30        cout << nextTerm << " ";
31    }
32    return 0;
33}
34