The Fibonacci Series is a sequence of numbers in which each number is the sum of the two preceding ones, usually starting with 0 and 1. The sequence looks like this:
0, 1, 1, 2, 3, 5, 8, 13, 21, 34, ...

Logic to Generate Fibonacci Series:

1. Start with the first two numbers in the Fibonacci series, typically 0 and 1.
2. For the next number, sum the two preceding numbers.
3. Repeat the process for the desired count of numbers in the series.

Program:

Here’s a simple C program to print the Fibonacci series up to a specified number of terms:

#include <stdio.h>

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

    // Input the number of terms from the user
    printf("Enter the number of terms: ");
    scanf("%d", &n);

    printf("Fibonacci Series: ");

    // Print the first two terms
    for (i = 1; i <= n; ++i) {
        if (i == 1) {
            printf("%d, ", t1); // First term
            continue;
        }
        if (i == 2) {
            printf("%d, ", t2); // Second term
            continue;
        }
        nextTerm = t1 + t2;  // Calculate the next term
        t1 = t2;             // Update t1 to the second term
        t2 = nextTerm;      // Update t2 to the new term
        printf("%d, ", nextTerm); // Print the next term
    }

    return 0;
}

Explanation:

1. Variables:

   • int n: This variable holds the number of terms in the Fibonacci series that the user wants to print.
   • int i: This is a loop counter.
   • int t1: This variable holds the first term in the series (initialized to 0).
   • int t2: This variable holds the second term in the series (initialized to 1).
   • int nextTerm: This variable is used to calculate the next term in the series.

2. Input:

   • The program prompts the user to enter the number of terms (n) they want in the Fibonacci series.

3. Fibonacci Calculation:

   • A for loop runs from 1 to n to generate the Fibonacci series.
   • First and Second Terms: The program prints the first two terms (0 and 1) separately.
   • Calculating Next Terms:
     • For subsequent terms, the program calculates the next term as the sum of the previous two terms: nextTerm = t1 + t2.
     • It then updates t1 and t2 to move to the next pair in the series.
     • The program prints each nextTerm.

4. Output:

   • The Fibonacci series is printed in a comma-separated format.

Sample Output:

Example 1:

Enter the number of terms: 5
Fibonacci Series: 0, 1, 1, 2, 3,

Example 2:

Enter the number of terms: 10
Fibonacci Series: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34,

Key Points:

• Iterative Approach: This program uses a simple iterative approach to generate the Fibonacci series.
• Variable Updates: The use of t1 and t2 helps keep track of the last two terms, making it easy to compute the next term.
• Basic Concepts: This program demonstrates basic programming concepts such as loops, conditionals, and input/output in C.