Why does this keep closing?

Well, after reading some source code, I wrote a text blackjack ( nothing too fancy, bare essentials ) and I compiled it. Compiles just fine, but when I try and run it, it closes immediately. What am I doing wrong?

Code:

/****************************************
* Text BlackJack Game
* Author: Cloud6
* Level: Beginner
****************************************/

#include <iostream>
using namespace std;

//declare player structure
struct Player
{
       unsigned int money;
       unsigned int wins, losses;
       bool won, lost;
};
Player player;  

void play();

int main()
{
    //declaring needed variables
    unsigned short input;
    unsigned short a = 0;
    
    //setting default stats
    player.money = 600;
    player.wins = 0;
    player.losses = 0;
    player.won = false;
    player.lost = false;
    
    //begin game
    cout<<"Welcome to Text BlackJack"<<endl;
    
    while(a)
    {
                   cout<<"\n\nPlease select your option."<<endl;
                   cout<<"1. Check money"<<endl;
                   cout<<"2. Play"<<std::endl;
                   cout<<"3. Review Status"<<endl;
                   cout<<"4. Quit"<<std::endl;
                   cin>>input;
                   switch(input)
                   {
                                case 1:
                                       cout<<"You currently have "<<player.money<<" dollars at your disposal.";
                                       break;
                                case 2:
                                       play();
                                       a = 1;
                                       break;
                                case 3:
                                       cout<<"\n\nWins: "<<player.wins<<" Losses: "<<player.losses<<".";
                                       break;
                                case 4:
                                       return 0;
                                       break;
                   }
                   a = 0;
                   
                   if (player.money == 0)
                   {
                                    cout<<"Out of money there..."<<endl;
                                    cout<<"Press any key to quit"<<endl;
                                    system("pause");
                                    return 0;
                   }
    }
    
    return 0;
}

void play()
{
//actual code goes here
// this part is not impoartant
}

Thanks in advance.

Code:

unsigned short a = 0;
...
while(a) { ... }

while(0) will never execute.

yeah, you probably want while(1)...I think.

Or initialize 1 to a and replace return 0; in the fourth case: with a = 0;.

Thanks! I changed it and now it runs just fine.