Implement Fibonacci sequence using javascript

Javascript method to implement Fibonacci sequence: 1. Use recursive method to implement, code such as "function fib(n){...}"; 2. Use for loop to implement, code such as "for( var i=2;i

The operating environment of this article: windows7 system, javascript version 1.8.5, Dell G3 computer.

JavaScript implements the Fibonacci sequence

The Fibonacci sequence, also known as the golden section sequence, refers to such a sequence: 1, 1, 2, 3, 5, 8, 13, 21... Starting from the 3rd number, each number is equal to the sum of the two numbers before it

Method 1: Recursion

function fib(n){
    if(n==1 || n==2){
        return 1;
    }
    return fib(n-1) + fib(n-2);
}

Method 2: for Loop implementation

function fb(n){
    var res = [1,1];
    if(n == 1 || n == 2){
        return 1;
    }      
    for(var i=2;i<n;i++){
        res[i] = res[i-1] + res[i-2];
    }
    return res[n-1];
}

or

function fb(n){
    var a,b,res;
    a = b = 1;
    for(var i=3;i<=n;i++){
        res = a + b;
        a = b;
        b = res;
    }
    return res;
}

[Recommended learning: javascript advanced tutorial]

The above is the detailed content of Implement Fibonacci sequence using javascript. For more information, please follow other related articles on the PHP Chinese website!