{"id":133,"date":"2010-12-03T10:33:27","date_gmt":"2010-12-02T23:33:27","guid":{"rendered":"https:\/\/learn-java-by-example.com\/?p=133"},"modified":"2011-07-22T15:25:36","modified_gmt":"2011-07-22T05:25:36","slug":"fibonnaci-number","status":"publish","type":"post","link":"https:\/\/learn-java-by-example.com\/java\/fibonnaci-number\/","title":{"rendered":"Fibonnaci Number"},"content":{"rendered":"<blockquote class=\"left-pull-quote\">\n<p><span style=\"font-size:20px;\">&rdquo;<\/span> By definition, the first two Fibonacci numbers are 0 and 1, and each subsequent number is the sum of the previous two. <span style=\"font-size:20px;\">&ldquo;<\/span><\/p>\n<p><cite>Fibonacci, <a href=\"http:\/\/en.wikipedia.org\/wiki\/Fibonacci_number\" target=\"_blank\">Wikipedia<\/a><\/cite><\/p><\/blockquote>\n<p>Generating Fibonacci numbers is an assignment often given to Java students when they are being introduced to recursion.<\/p>\n<p>Recursion is programming technique that involves a method calling itself to solve a problem. When implementing a recursive solution we look for two things:<\/p>\n<ul>\n<li>A base case that returns a value without any subsequent recursive calls.<\/li>\n<li>A reduction step that relates the methods inputs to other inputs that converge oto the base case.<\/li>\n<\/ul>\n<p>It is worth mentioning that using recursion to generate Fibonacci numbers is actually quite inefficient, and is really only useful as a learning exercise.<\/p>\n<pre class=\"brush: java; title: ; notranslate\" title=\"\">\r\npackage com.learnjava.math;\r\n\r\n\/**\r\n * Write a Java program that generates the \r\n * first 10 Fibonacci numbers using recursion..\r\n * \r\n * @author https:\/\/learn-java-by-example.com\r\n *\r\n *\/\r\n\r\npublic class Fibonacci {\r\n\r\n\t\/**\r\n\t * Retuens fibonacci number for n\r\n\t * @param n\r\n\t * @return fibonacci number for n\r\n\t *\/\r\n\tpublic static int fibonacci(int n) {\r\n\t\tif (n&lt;=1) {\r\n\t\t\t\r\n\t\t\t\/\/ By definition, the first two Fibonacci numbers are 0 and 1\r\n\t\t\t\/\/ This is our base case\r\n\t\t\t\r\n\t\t\treturn n;\r\n\t\t\r\n\t\t} else {\r\n\t\t\t\r\n\t\t\t\/\/ and each subsequent number is the sum of the previous two\r\n\t\t\t\/\/ Remember that Java passes parameters by value, this\r\n\t\t\t\/\/ means this method uses a local copy of n\r\n\t\t\t\r\n\t\t\treturn fibonacci(n-1) + fibonacci(n-2);\r\n\t\t}\r\n\t}\r\n\r\n\tpublic static void main(String[] args) {\r\n\t\t\r\n\t\tfor (int n = 0; n&lt;10; n++) {\r\n\t\t\tint fibonacci = fibonacci(n);\r\n\t\t\tSystem.out.print(fibonacci+&quot;, &quot;);\r\n\t\t}\r\n\t\tSystem.out.println(&quot;...&quot;);\r\n\t}\r\n\r\n}\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Generating Fibonacci numbers is an assignment often given to Java students when they are being introduced to recursion. Recursion is programming technique that involves a method calling itself to solve a problem. When implementing a recursive solution we look for two things: A base case that returns a value without any subsequent recursive calls. A&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"jetpack_publicize_message":"","jetpack_is_tweetstorm":false,"jetpack_publicize_feature_enabled":true,"jetpack_social_options":[]},"categories":[4],"tags":[29,30,13],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p6Yyl2-29","jetpack-related-posts":[{"id":78,"url":"https:\/\/learn-java-by-example.com\/java\/check-palindromes-using-recursion\/","url_meta":{"origin":133,"position":0},"title":"Check Palindromes using Recursion","date":"June 1, 2011","format":false,"excerpt":"A popular problem is how to determine if a String is a Palindrome or not, the following will also assume we are only dealing with Palindromes of single words ie. no spaces or punctuation. The way to determine this is to compare the characters on the left and right ends\u2026","rel":"","context":"In &quot;Java&quot;","img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":43,"url":"https:\/\/learn-java-by-example.com\/java\/palindromes\/","url_meta":{"origin":133,"position":1},"title":"Palindromes","date":"April 13, 2011","format":false,"excerpt":"A popular problem is how to determine if a String is a Palindrome or not, the following will also assume we are only dealing with Palindromes of single words ie. no spaces or punctuation. The way to determine this is to compare the characters on the left and right ends\u2026","rel":"","context":"In &quot;Featured&quot;","img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":56,"url":"https:\/\/learn-java-by-example.com\/java\/monthly-payment-calculator\/","url_meta":{"origin":133,"position":2},"title":"Monthly Payment Calculator","date":"June 2, 2010","format":false,"excerpt":"This is the simplest form of one of the classic problems given to first year Java students. It aims to get you comfortable with the structure of a simple Java application and how to get input from the user. User input in this example is taken from the console (standard\u2026","rel":"","context":"In &quot;Java&quot;","img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":154,"url":"https:\/\/learn-java-by-example.com\/java\/prime-numbers\/","url_meta":{"origin":133,"position":3},"title":"Prime numbers","date":"January 21, 2011","format":false,"excerpt":"The assignment here is to calculate all prime numbers less than 100. The solution provided uses the following to determine if a given number is prime. 2 is prime Any number divisible by 2 is not prime If the number is divisible by any odd number then it is not\u2026","rel":"","context":"In &quot;Java&quot;","img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":238,"url":"https:\/\/learn-java-by-example.com\/java\/selection-sort\/","url_meta":{"origin":133,"position":4},"title":"Selection Sort","date":"June 19, 2015","format":false,"excerpt":"When you are learning Java you are very likely going to be asked to write a program to sort values. We will start with one of the simpler sort algorithms, the Selection Sort (also known as an Exchange Sort). It's not a particularly efficient algorithm and really only suitable for\u2026","rel":"","context":"In &quot;Java&quot;","img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":199,"url":"https:\/\/learn-java-by-example.com\/java\/pythagoras-theorem\/","url_meta":{"origin":133,"position":5},"title":"Pythagoras Theorem","date":"December 13, 2010","format":false,"excerpt":"One of our member students was asked to implement the Pythagoras Theorem using Java. This is a good opportunity to introduce the Math class which contains a collection of static methods for various mathematical functions. We need the square root method (sort) to calculate the hypotenuse, and can also use\u2026","rel":"","context":"In &quot;Java&quot;","img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]}],"_links":{"self":[{"href":"https:\/\/learn-java-by-example.com\/wp-json\/wp\/v2\/posts\/133"}],"collection":[{"href":"https:\/\/learn-java-by-example.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/learn-java-by-example.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/learn-java-by-example.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/learn-java-by-example.com\/wp-json\/wp\/v2\/comments?post=133"}],"version-history":[{"count":5,"href":"https:\/\/learn-java-by-example.com\/wp-json\/wp\/v2\/posts\/133\/revisions"}],"predecessor-version":[{"id":135,"href":"https:\/\/learn-java-by-example.com\/wp-json\/wp\/v2\/posts\/133\/revisions\/135"}],"wp:attachment":[{"href":"https:\/\/learn-java-by-example.com\/wp-json\/wp\/v2\/media?parent=133"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/learn-java-by-example.com\/wp-json\/wp\/v2\/categories?post=133"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/learn-java-by-example.com\/wp-json\/wp\/v2\/tags?post=133"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}