C Tutorial

C Tutorial C Language Environment Setup Execution flow of C program C printf and Scanf C Data type C Token Variable in C Operators in C Comments in C Escape Sequence in C C – Storage Classes C Decision control statement Loop Statement in C Break, continue and goto statement in C Type Casting in C Function in C Recursion in C String in C C Array Pointer in C Dynamic memory allocation C –Structure Nested Structure in C Union in C File Handling in C C pre-processor Static Function In C Sizeof In C Selection Sort In C Scope Of Variables In C Runtime Vs Compile Time In C Random Access Lseek In C Queue Implementation In C Pseudo Code In C Prototype In C Pointer To Pointer In C Pointer Arithmetic In C Passing Array To Function In C Null Character In C Merge Sort In C Macros In C Library Functions In C Memory Leak In C Int In C Goto And Labels In C Fibonacci Series In C Fflush In C Derived Data Types In C Data Types In C Const Vs Volatile In C Character Set In C Character Class Tests In C Calloc In C C Pointers Arrays In C Include In C Clrscr In C C Vs Java String Literals In C Types Of Pointers In C Variables In C Volatile In C Why C Is A Middle Level Language Infix To Postfix Program In C Ceil function in C LCM of two numbers in C Quick sort in C Static in C function pointer as argument in C Top Array Keywords in C Add two numbers using the function in C Armstrong program in C using function Array, Declaring Arrays and Array Initialization Limitations of Inline Function in C Merge and Merge sort with example in C Do-While Loop in C For Loop in C While-Loop in C Difference between while and do-while loop in C Array Of Structures in C Data Structures And Algorithms in C Types Of Structures In C How to Avoid Structure Padding in C Use of Structure in C Do WHILE LOOP in C Programming Examples For Loop in C Programming Examples Entry Control Loop in C Exit control loop in C Infinite loop in C Nested loop in C pow() function in C String Handling functions in C Prime Number code in C Factorial Program in C using For Loop Factorial Program in C Using While Loop Fibonacci Series in C Using For Loop Fibonacci series in C using while loop Prime Number Program in C using for Loop While Loop in C programming examples Built-in functions in C Assert() Function C vs Java Strings Call Back Function in Embedded C Else If Ladder fgets() function Ftell() Function getc() function getch() function gets() function Heap Sort Nested if-else statement Pi() Function Positioning of file Write() function abs() function in C Attributes in C C program to find factorial of a number using Recursion Ferror() in c fopen() function in C Fibonacci series program in C using Recursion Formatted Input and output function in C Snake Game in C User Defined Functions in C Beep() function in C Cbrt() function in C Hook() function in C Isalnum() function in C C Program to find the Roots of a Quadratic Equation C Switch Statements Difference between rand() and srand() function in C Difference between while and for loop in C Doubly Linked list in C Example of Iteration in C How to use atoi() function in C How to use floor() function in C How to use sine() function in C How to use Typedef Struct in C Integer Promotions in C C Program to Find Largest Number Using Dynamic Memory Allocation C Program to Find the Largest Number using Ternary Operator C/C++ Program to Find the Size of int, float, double and char Find the Largest Three Distinct Elements in an Array using C/C++ Loop Questions in C Modulus on Negative Numbers in C Multiplication table program in C using For loop Nested Loops in C Programming Examples C Program for Mean and Median of an Unsorted Array Results of Comparison Operations in C and C++ Reverse a Stack using Recursion in C Simple hash() function in C strcat() Function in C Sum of N numbers in C using For loop Use of free() function in C Write a program that produces different results in C and C++

Fibonacci Series in C Using For Loop

In this C article, we will let you know about the procedure of displaying the Fibonacci series of the first “n” positive integers.

The syntax of for loop used in the C programming language is:

for (initialization statement; termination condition; increment or decrement statement (used for modifying value for further evaluation))
{
    /* main body of the “for” loop */
}

Working of the for loop in C

In for loop, the initialization command is implemented only once. After that, it checks the test expression of the loop and finds whether the test expression is false or true. And, for loop is dismissed if the test expression is false.   

If the test expression of the 'For loop becomes true, then the program line provided in the For loop’s body is executed, and the update expression is changed accordingly.

Again, the entire process of evaluation is to be done. The loop executes its body until and unless the value of the test expression in for loop becomes false. The loop automatically terminates as soon as the test expression result becomes false.

What is Fibonacci Series?


In the Fibonacci series, the next coming term is the sum of the previous two terms. But, 0 and 1 are always considered as the first two terms in the Fibonacci series.

The Fibonacci series commence like:
0, 1, 1, 2 and so on.

Program of Fibonacci series up to the given nth terms:

#include <stdio.h>
int main() 
{
  int a, b;
  // declaring variables and initializing first and second terms without value
  int c1 = 0, c2 = 1; // declaring the value of term 1 as c1 = 0 and term 2 as c2 = 1 
  // initializing the upcoming third term (upterm) 
  int upterm= t1 + t2;
  printf("Enter the no. of terms of the Fibonacci series you want to print: "); // taking input from the user about the no. of terms user wants to print
  scanf("%d", &b); // assigning the value entered by the user to b
  printf("Fibonacci Series is as follow: %d, %d, ", c1, c2); // printing the values of the first two declared as terms c1 and c2
  for (a = 3; a <= n; ++a) // (initialization statement; termination condition; increment or decrement statement) 
// printing the 3rd term and to the nth terms 
{
    printf("%d, ", upterm);
    c1 = c2;
    c2 = upterm;
    upterm = c1 + c2;
  }
  return 0;
}

Output:

Enter the no. of terms of the Fibonacci series you want to print: 8
Fibonacci Series is as follow: 0 1 1 2 3 5 8 13 

Explanation:
Let us suppose the number entered by the user is 10 for b variable. Initially, we will have to print the first two terms of the Fibonacci series prior to using a “for” loop which prints the upcoming b terms.

Let us see how the for loop works in the following table:

Value of aValue of c1Value of c2uptterm
3011
4112
5123
6235
7358
85812

Program to print the Fibonacci Series Up to a Certain Number:

#include <stdio.h>
int main() 
{
  int c1 = 0, c2 = 1, upterm = 0, b;
  printf("Enter the no. of terms of the Fibonacci series you want to print: ");
  scanf("%d", &b); // assigning the value entered by the user to b
  printf("Fibonacci Series is as follow: %d, %d, ", c1, c2); // printing the values of the first two declared as terms c1 and c2
 upterm = c1 + c2;
  while (nextTerm <= b) // (termination condition of the while loop)  
{
    printf("%d, ", upterm);
    c1 = c2;
    c2 = upterm;
    upterm = c1 + c2;
  }
  return 0;
}

Output:

Enter the no. of terms of the Fibonacci series you want to print: 100
Fibonacci Series is as follow: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 

In this program, we have used a while loop to print all the Fibonacci numbers up to nth terms.

Suppose, if the value of ‘b’ is considered as part of the Fibonacci series, then we will just print the Fibonacci series up to the natural positive number  which is closest and lesser than the value of b entered by the user.

The following table describes how the for loop works in the above program:

t1       t2       uptterm             uptterm <= n

0        1           1                  true. Print uptterm.

1        1           2                  true. Print uptterm.

1        2           3                  true. Print uptterm.

...       ...          ...          ...

34      55         89                true. Print uptterm.

55      89         144              false. Terminate Loop.



ADVERTISEMENT
ADVERTISEMENT