CODEWITHSUNDEEP
c++fibonaccidev-c++
GanimEdes
GanimEdes

Reputation: 23

What's wrong with this code? Fibonacci series

It should print the Fibonacci series up until a position, but it just prints 1 1 2, even if I ask for more than the first three elements. How can I fix this?

#include <iostream>
using std::cout;
using std::cin;

int main()
{
    cout << "Enter a number: ";
    int number;
    cin >> number;
    int count = 1;
    int a = 1;                  //The first number of the Fibonacci's serie is 1
    int b = 1;                  //The second number of the Fibonacci's serie is 2
    while (count <= number)
    {
        if (count < 3)
            cout << "1 ";
        else
        {
            number = a + b;     //Every number is the sum of the previous two
            cout << number << " ";
            if (count % 2 == 1)
                a = number;
            else
                b = number;
        }
        count++;
    }

    return 0;
}

Upvotes: 1

Views: 92

Answers (3)

Avinash354
Avinash354

Reputation: 1

You can try this code:

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;
}

Upvotes: -2

M Umer
M Umer

Reputation: 403

It is like swapping the variable's values. You're using the number as limitation but in the loop you're using the same variable that is creating a logical error. Do the following changes and you're done (Y).

int main()
{
cout << "Enter a number: ";
int number;
cin >> number;
int count = 1;
int a = 1;                  //The first number of the Fibonacci's serie is 1
int b = 1; 
int i = 1;                 //The second number of the Fibonacci's serie is 2
while (i <= number)
{
    if (i < 3)
        cout << "1 ";
    else
    {
        count = a + b;     //Every number is the sum of the previous two
        a = b;
        b = count;
        cout << count << " ";
    }
    i++;
}

return 0;
}

Upvotes: 1

Bill the Lizard
Bill the Lizard

Reputation: 405715

You're using number as the maximum number of loop iterations here:

while (count <= number)

But then inside the loop you're using the same variable as the current Fib value to output for each iteration.

number = a + b;     //Every number is the sum of the previous two
cout << number << " ";

That's causing the loop to terminate prematurely. You need to pick different variable names for these two different values.

Upvotes: 2

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