switch between true and false state

Question

I have an object representing a player and let us say 2 players

//create a player object
function player(name,state,score) {
    this.name = name;
    this.state = state;
    this.score = score;
} 

 var players = [
new player('player1',true,0),
new player('player2',false,0)
];

so I want the players to make a move one after another. For that purpose I use true or false state. So when true, it counts (I count the right answers of player and display them) for player 1 and vs.

what I have for now is

$("#check").click(function(){
if(localCorrect == 2){

//counting number of correct cards and assigning it to the player
    var i=0; 
        if (players[i].state == true){
        var localscore = players[i].score;
        localscore++;
        score[i] = localscore;
//display the score
        $("span#"+players[i].name).html(score[i]);

        players[i].state = false;
        i++;
        players[i].state = true;
        //if(i=2)
        //{i=0}
        }

}else{
//some other thing
    }
});

I have a feedle with this http://jsfiddle.net/ycycghwq/

So I have 2 question:

1. I think I'm wrong with the declaration of var i (it represents an index of a player, I have 2 of them so it should count to 1 and then go back to 0 at this point. But I want to make it not dependant on a particular number, so that it could be 4 or 10 players.

2. I need to switch the state of the current player(i). player1 needs to be true and when switch to false. then the state of player 2 needs to be swithced from false to true. (So if I have more that 2 players I need to switch the state of the following one to true and the to false)

My brain of the beginner is boiling. Could someone please help?! Thanks in advance!

Answer 1

• Answer 1:

Declare i outside of your handler before its setup. Instead of i++; write i = (i+1) % num_of_players; and define the variable num_of_players; % is the modulo operator computing the remainder of a division. If used as outlined it repeatedly iterates from 0 to num_of_players-1. Using players.length in place of num_of_players is equivalent.

• Answer 2:

The players' states are initialize when you create the player objects. In your given code replace players[i].state = false;, players[i].state = true; with players[i].state = !players[i].state;.

Working demo: this fiddle.

Note

• You needn't use the equality test operator on boolean variables; if (players[i].state) { ... will suffice.

• If you use test for equality, use the type-safe variant === instead of ==.

Answer 2

I modified your code a bit. Now you can have x number of players in the array and they will switch their states just fine. I commented the most important parts so I don't think you will have problem reading the code. If you have just ask :)

JSFiddle: http://jsfiddle.net/ycycghwq/2/

var score = [0,0];
var localCorrect = 2;

$(document).ready(function(){

//create a player object
var Player = function(name, state, score) {
    this.name = name;
    this.state = state;
    this.score = score;
} 

var players = [
    new Player('player1',true,0),
    new Player('player2',false,0)
];

$("#check").click(function(){
    if(localCorrect == 2) {
        // iterate through all the players
        for(var iterator = 0; iterator < players.length; iterator++) {
            // check if there is array/object element with this key
            if (players.hasOwnProperty(iterator)) {
                var player = players[iterator];

                // check for player state
                if (player.state === true) {
                    // increment player score
                    player.score++;
                    score[iterator] = player.score;

                    $("span#" + player.name).html(score[iterator]);
                    player.state = false;

                    // check if there is next player in the array
                    // if not start from the first player
                    if (players.hasOwnProperty(iterator + 1)) {
                        var nextPlayer = players[iterator + 1];
                        nextPlayer.state = true;
                    } else {
                        var firstPlayer = players[0];
                        firstPlayer.state = true;
                    }

                    // exit the for loop
                    break;
                } else {
                    // some other thing
                }
            }
        }
    }
});
});

EDIT:

You don't create variable in players object/array. You create a variable iterator for the for..in loop. That variable represents each key of the array (in this case players). So your iterators will be 0 and 1 for the 2 iterations of the loop. You can use that also to iterate through objects and to get their property names and much more.

Documentation of for..in loop

Anyway it's my bad to use for..in loop and not a sequential for loop in this situation:

for(var iterator = 0; iterator < players.length; iterator++)

That way we don't need to parse the iterator to integer. Read more about when to use for..in loop and when sequential for loop:

• here
• and here