December 23, 2022, Learn eTutorial

1456

**The Fibonacci series is a sequence of numbers in which the first numbers will be 0 and 1 From the next number onwards, numbers in the series will be the sum of the previous two numbers.** For example, 0,1,1,2,3,5,8... where every number will be the sum of two previous numbers.

In this C program, we need to generate the Fibonacci numbers up to a given number, which means if the user enters a value of 10, we have to Calculate the Fibonacci Series below 10. In our previous Fibonacci program, we calculated '**n'** Fibonacci numbers, which means if the user enters 10, we have to find the 10 Fibonacci numbers.

Here in this C program, after we have the user input in a variable called '**num**,' we compare the num with the '**sum**' variable. If the '**Sum**' is greater than the '**num**', we have to stop generating the series.

To implement Fibonacci logic, we have to Declare some integer variables **'t1', 't2',** '**sum**'. First set '**sum=0**', '**t1=0**', and '**t2=1**'. Then read the Limit of the Series into the integer variable **num**. Display the First two integer variables as '**t1**' and '**t2**'. Means **'**0' and '1', and make the next number as the Sum of '**t1**' and '**t2**'. Then open a while loop until **Sum** is less than **num**, then in the loop print sum, then interchange the values of** t1 =t2 and t2 = sum. **and again calculate the** sum as t1 + t2.**

STEP 1: Include the Header files to use the built-in functions in the C program.

STEP 2: Declare the integer variables "**sum, num, t2, t1 **and set **sum=0, t1=0, t2=1**".

STEP 3: Read the Limit to generate the Fibonacci Series from the user and store it into **num**.

STEP 4: Display the first two numbers of the Fibonacci Series as **0** and **1**.

STEP 5: Find **sum=t1+t2**. Which is the next element in the Fibonacci Sequence.

STEP 6: By using a '`while loop`

' check the **Sum is less than num**.

STEP 7: Then Assign '**t1=t2**' and '**t2=sum**'.

STEP 8: Calculate '**sum=t1+t2**' and repeat step 6.

For generating the Fibonacci series, we have to use the below C programming concepts. we recommend learning those for a better understanding

` ````
#include <stdio.h>
int main()
{
int t1 = 0, t2 = 1, sum = 0, num; /* declaring the variables sum and num */
printf("Enter an integer: "); /* enters and reads a number from user */
scanf("%d", & num);
printf("Fibonacci Series: %d,%d,", t1, t2); /* now printing first two numbers in Fibonacci series */
sum = t1 + t2;
while (sum < num)
{
printf("%d,", sum);
t1 = t2; /* checking and displaying the Fibonacci numbers upto number user inputs */
t2 = sum;
sum = t1 + t2;
}
} /* main ends */
```

Enter the limit to generate the Fibonacci sequence 10 Fibonacci sequence is ... 0,1,1,2,3,5,8