Basic concepts of functions and the use of recursion

Function

1.//basic functions, learn to call functions:

how ();//Call function, anywhere can call    //output a sentence    function show ()    {         alert ("This is a simple function");     }    Show ();//Call function, anywhere can call

2.//functions with parameters

Function Show (a)//a is called the formal parameter, the formal argument {    alert (a);}    Show ("parameters");//arguments, actual parameters

3.//functions with multiple parameters

function sum (A, B)//The name of the formal parameter can be arbitrarily {    alert (a+b);}    SUM (1+2);//Set parameters for A and B, respectively

4.//function with return value

function sum (A, b) {    return a+b;//return value a plus a    a=sum (3,4);//Set Parameter    alert (a);//js the function is often used where the event// Other language functions are used in the word encapsulation function

Several important functions:

1. Random number generator: Math.random ()
2.random () returns a random number between 0 and 1
3.substr ********
Returns a substring of a string in which the incoming parameter is the starting position and length
4.replace *******
Replace String, the first argument represents the replaced string, the second argument represents the replacement string
5.split ******
Make a string into a string array by dividing the string into substrings
6.length attribute *******
Returns the length of a string, the length of which is the number of characters it contains

Recursion!
1. There are 200 peaches in the park, the monkeys eat 10 a day, pick out two bad throw away, ask 6 days after the remaining number of peaches? (first with a loop)

var sl=200//total number of peaches for (var i=0;i<6; i++) {    sl=sl-10-2;     }    alert (SL);

2. There are a bunch of peaches in the park, the monkeys eat half a day, pick a bad throw away, the 6th day found that there are 1 peaches left, asked how many peaches? (Made with a loop)

var sl=0;for (i=0;i<6; i++) {    sl= (sl+1)* *}    alert (SL);

3. Use the function to find the above topic (recursion)
Function: Returns the number of peaches in the nth day
Use the meaning of the function itself to make itself a variable in the equation or arithmetic, participate in the operation!

var sl;//defines the number of peaches as Slfunction Shuliang (n) {        ///when n equals 6 peaches is 1    if (n==6)    {        sl=1;    }    else {//the number of days//number of day        = (number of next day + 1) * *        sl= (Shuliang (n+1) +1) * *;    }        return SL; Returns the number of the day}    alert (Shuliang (0));

Basic concepts of functions and the use of recursion