# C Program to generate Fibonacci sequence

Last updated on September 23, 2020

## What is Fibonacci sequence? #

Fibonacci sequence is series in which each successive number is the sum of the previous two numbers. For example:

1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144


The following is a C program to generate Fibonacci sequence based on the number of terms entered by the user.

  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 /******************************************************* * Program to generate Fibonacci sequence ********************************************************/ #include // include stdio.h int main() { long int x = 0, y = 1, z; int terms, i = 1; printf("Enter no. of terms: "); scanf("%d", &terms); // to suppress the compiler warning in Linux replace %d with %zu printf("%d ", y); while(i <= terms - 1) { z = x + y; x = y; y = z; printf("%d ", z); // to suppress the compiler warning in Linux replace %d with %zu i++; } return 0; } 

## How it works #

The following table demonstrates what happens at each iteration of the loop (assuming terms = 5)

Iteration z x y i
After 1st iteration z = x + y = 0 + 1 = 1 x = y = 1 y = z = 1 i = 2
After 2nd iteration z = 1 + 1 = 2 x = 1 y = 2 i = 3
After 3rd iteration z = 1 + 2 = 3 x = 2 y = 3 i = 4
After 4th iteration z = 2 + 3 = 5 x = 3 y = 5 i = 5