CC-9 : Generate first N Fibonacci numbers.

Description:

Fibonacci numbers are a series where each number is the sum of the two previous numbers. The series starts from 0 and 1, so the series generated 0, 1, 1, 2, 3, 5, 8... Given an input number N, find the first N Fibonacci numbers.

Test cases and expected outputs:

Input Parameters	Expected outputs
Number: 3	First 3 Fibonacci numbers: 0 1 1
Number: 9	First 9 Fibonacci numbers: 0 1 1 2 3 5 8 13 21

Pseudocode:

generateFibonacci(n):

If num==0, return 0; (base case).

If num==1, return 1.

Find the sum of recursive calls to generateFibonacci(n-1) and generateFibonacci(n-2).

printFibonacci(n):

• Iterate through using for loop with idx as iteration variable and values of idx ranging from 0 to n:

o Call generateFibonacci(idx) and print the return value.

Code:

private int generateFibonacci(int n){
	if (n == 0) {
		return 0;
	}else if (n==1){
		return 1;
	}else {
		return generateFibonacci(n-1)+ generateFibonacci(n-2);
	}
}

public void printFibonacci(int n) {
	for (int iIdx=0; iIdx < n;iIdx++) {
		System.out.println(generateFibonacci(iIdx));
	}
}

Click here to download and run code and test cases !

Below fully running code can be copied and run on Eclipse or other Java IDEs. Refer the classname in code below. If the class name below is "A", save the code below to a file named A.java before running it. Be sure to try your own test cases to enhance your understanding ! You can also tweak the code to optimize or add enhancements and custom features.

public class RecursionGenerateFibonacci {

private int generateFibonacci(int n){
	if (n == 0) {
		return 0;
	}else if (n==1){
		return 1;
	}else {
		return generateFibonacci(n-1)+ generateFibonacci(n-2);
	}
}

public void printFibonacci(int n) {
	for (int iIdx=0; iIdx < n;iIdx++) {
		System.out.println(generateFibonacci(iIdx));
	}
}


public static void main(String[] args) {
	/**********************
	 Test cases given below
	 *********************/
	int retVal;
	try {
	
	RecursionGenerateFibonacci rcn=new RecursionGenerateFibonacci();
	int num=3; 
	System.out.println("First "+num+ " Fibonacci numbers: ");
	rcn.printFibonacci(num);
	System.out.println();
	num=9; 
	System.out.println("First "+num+ " Fibonacci numbers: ");
	rcn.printFibonacci(num);	
	
	}catch (Exception exception) {
		System.out.print("Exception: "+ exception);
		exception.printStackTrace();
	}
		
}

}