1 0 game

//variables
     var wallet = 0;
     var a = 0;
     var roundlength = prompt ('length of the game?');
     if (roundlength == '')
     {roundlength = 5;}
//prompt   (how long does the game go?);

 do  {var playerinput = prompt('1 or 0, your guess!');
// prompt    (1 or 0? (avoid other characters!));

//introduces the game
console.log('1', '0', 'game!', '');

//asks if youd like an explanation
var question = prompt
("would you like an explanation?  1/0?")
switch(question){
       //y or n switch statement
    case '1':

    console.log
    ("the goal of the game is to get more points by luck, guess one or zero, if the computer generates a one and you choose one, you get a point! otherwise if it doesnt match then you lose a point!", "");

        break;

    case '0':

        break;

    case '':
    break;

        default:
    console.log
    ("that is not a valid input");
}

//math for 0 or 1.
for (var x = 0; x < roundlength; x++) {
    var numberRand = Math.random();
        if (numberRand < 0.5)
         {numberRand = 0} //for 0
else {numberRand = 1}; //for 1
     console.log('[RNG]' +numberRand);
        //prints it
        switch(numberRand) {
            case 1:

             switch(playerinput) {
                case '1':
                ++wallet;
                console.log('[W]' + wallet);
                break;

                case '0':
                --wallet;
                console.log('[w]' + wallet);
                break;}
            break;

            case 0:

            switch(playerinput) {
                case '1':
                --wallet;
                console.log('[w]' + wallet);
                break;

                case '0':
                ++wallet;
                console.log('[w]' + wallet);
                break;
            }
            break;
    }
 }
}
while (a > 0);