treatment "double-auction.ztt"{
	background{
		table globals{
		}
		table subjects{
		}
		table summary{
		}
		table contracts{
		}
		table clients{
		}
		table treatments{
		}
		table sessionglobals{
		}
		table participations{
		}
		numsubjects = 8;
		numgroups = 1;
		numpracticeperiods = 0;
		numactualperiods = 2;
		exchangerate = 1;
		startendowment = 0;
		showupfee = 0;
		noAutoscope = FALSE;
		firstBoxesOnTop = FALSE;
		showupfeeawaytext = "You are making losses. Do you want to invest the showupfee in order to continue?";
		showupfeeawayyestext = "Yes";
		showupfeeawaynotext = "No";
		moneyawaytext = "You are  making losses. Do you want to continue?";
		moneyawayyestext = "Yes";
		moneyawaynotext = "No";
		bancruptwaittext = "Please wait until the experimenter unlocks your PC.";
		program{
			table = globals;
			do{
				TradingTime = 120;
			}
		}
		program{
			table = subjects;
			do{
				// Unit k is worth Values[k] to a buyer, and costs a seller Costs[k].
						array Values[4];
						Values[1] = 400;
						Values[2] = 300;
						Values[3] = 200;
						Values[4] = 200;
						array Costs[4];
						Costs[1] = 20;
						Costs[2] = 120;
						Costs[3] = 220;
						Costs[4] = 220;
						MaxUnits = 4;
						MaxPrice = 1000;
						UnitsTraded = 0;
			}
		}
		program{
			table = contracts;
			do{
				// An offer: a bid has Buyer (its maker) and Seller = -1; an ask the other way round.
						// A trade has both; a withdrawn offer has -2 for the side it lacked.
						Buyer = 0;
						Seller = 0;
						TradePrice = 0;
			}
		}
		screen action{
			usesbg = TRUE;
			withalertscreen = FALSE;
			noalertscreen = FALSE;
			headerbox "Header"{
				hasframe = TRUE;
				height = 10%;
				top = 0p;
				cuttop = TRUE;
				showPeriods = TRUE;
				showNumPeriods = TRUE;
				periodtext = "Period";
				periodoftext = "of";
				practiceperiodprefix = "Trial ";
				showtime = TRUE;
				timestr = "Remaining time [sec]:";
				pleasedecidetext = "Please reach a decision.";
			}
		}
		screen wait{
			usesbg = TRUE;
			withalertscreen = FALSE;
			noalertscreen = FALSE;
			standardbox "Text"{
				hasframe = TRUE;
				buttonposition = BOTTOMRIGHT;
				buttonsequence = HORIZONTAL;
				item{
					label = "Please wait until the experiment continues.";
				}
			}
		}
	}
	stage "Buyers"{
		startwaitforall = TRUE;
		startConditionStr = "";
		singleentry = FALSE;
		singleentrycontinuation = FALSE;
		timeouttype = always;
		timeout = TradingTime;
		program{
			table = subjects;
			do{
				// Players 1 to 4 buy, 5 to 8 sell.
						IsBuyer = if(Player <= 4, 1, 0);
						Participate = IsBuyer;
			}
		}
		screen action{
			usesbg = TRUE;
			withalertscreen = FALSE;
			noalertscreen = FALSE;
			standardbox "You"{
				hasframe = TRUE;
				width = 30%;
				left = 0;
				cutleft = TRUE;
				buttonposition = BOTTOMRIGHT;
				buttonsequence = HORIZONTAL;
				item{
					label = "You are a buyer.";
				}
				item{
					label = "Units traded";
					variable = UnitsTraded;
					format = "1";
					input = FALSE;
				}
				item{
					label = "Your next unit is worth";
					variable = Values[UnitsTraded + 1];
					format = "1";
					input = FALSE;
				}
				item{
					label = "Profit so far";
					variable = Profit;
					format = "1";
					input = FALSE;
				}
			}
			makecontractbox "Make an offer"{
				hasframe = TRUE;
				width = 40%;
				table = contracts;
				buttonposition = BOTTOMRIGHT;
				buttonsequence = HORIZONTAL;
				emptyallowed = FALSE;
				allemptyallowed = FALSE;
				numrecords = 1;
				tablelayout = VERTICAL;
				item{
					label = "Price";
					variable = Price;
					format = "1";
					input = TRUE;
					showdefault = FALSE;
					emptyallowed = FALSE;
					min = 0;
					max = MaxPrice;
				}
				button "Bid"{
					clearinputafterok = FALSE;
					norecordmadeorselected = FALSE;
					terminatestage = FALSE;
					donotterminatestage = FALSE;
					specialbuttoncolor = FALSE;
					buttoncolor = 0;
					checker{
						condition = :UnitsTraded < MaxUnits;
						message = "You have traded all your units.";
						yesButtonStr = "";
						noButtonStr = "OK";
					}
					checker{
						condition = contracts.count(Seller == -1 & Buyer > 0) == 0 | Price > contracts.maximum(Seller == -1 & Buyer > 0, Price);
						message = "Your bid must be higher than the best bid.";
						yesButtonStr = "";
						noButtonStr = "OK";
					}
					program{
						table = contracts;
						do{
							Buyer = :Subject;
							Seller = -1;
						}
					}
				}
			}
			selectcontractbox "Asks"{
				hasframe = TRUE;
				width = 30%;
				table = contracts;
				buttonposition = BOTTOMRIGHT;
				buttonsequence = HORIZONTAL;
				emptyallowed = FALSE;
				allemptyallowed = FALSE;
				condition = Buyer == -1 & Seller > 0;
				sortfields = "Price";
				tablelayout = LIST;
				scrollatstart = FALSE;
				scrollatEnd = FALSE;
				selectbest = TRUE;
				item{
					label = "Ask";
					variable = Price;
					format = "1";
					input = FALSE;
				}
				button "Buy"{
					clearinputafterok = FALSE;
					norecordmadeorselected = FALSE;
					terminatestage = FALSE;
					donotterminatestage = FALSE;
					specialbuttoncolor = FALSE;
					buttoncolor = 0;
					checker{
						condition = :UnitsTraded < MaxUnits;
						message = "You have traded all your units.";
						yesButtonStr = "";
						noButtonStr = "OK";
					}
					program{
						table = contracts;
						do{
							Buyer = :Subject;
									TradePrice = Price;
									subjects.do {
										if (Subject == :Buyer) {
											UnitsTraded = UnitsTraded + 1;
											Profit = Profit + Values[UnitsTraded] - :Price;
										}
										if (Subject == :Seller) {
											UnitsTraded = UnitsTraded + 1;
											Profit = Profit + :Price - Costs[UnitsTraded];
										}
									}
									// The traders' other offers are withdrawn.
									contracts.do {
										if (Seller == :Seller & Buyer == -1) {
											Buyer = -2;
										}
										if (Buyer == :Buyer & Seller == -1) {
											Seller = -2;
										}
									}
						}
					}
				}
			}
			selectcontractbox "Bids"{
				hasframe = TRUE;
				width = 30%;
				table = contracts;
				buttonposition = BOTTOMRIGHT;
				buttonsequence = HORIZONTAL;
				emptyallowed = FALSE;
				allemptyallowed = FALSE;
				condition = Seller == -1 & Buyer > 0;
				sortfields = "-Price";
				tablelayout = LIST;
				scrollatstart = FALSE;
				scrollatEnd = FALSE;
				selectbest = FALSE;
				item{
					label = "Bid";
					variable = Price;
					format = "1";
					input = FALSE;
				}
			}
			selectcontractbox "Trades"{
				hasframe = TRUE;
				width = 30%;
				table = contracts;
				buttonposition = BOTTOMRIGHT;
				buttonsequence = HORIZONTAL;
				emptyallowed = FALSE;
				allemptyallowed = FALSE;
				condition = Buyer > 0 & Seller > 0;
				sortfields = "";
				tablelayout = LIST;
				scrollatstart = FALSE;
				scrollatEnd = FALSE;
				selectbest = FALSE;
				item{
					label = "Price";
					variable = TradePrice;
					format = "1";
					input = FALSE;
				}
			}
		}
		screen wait{
			usesbg = TRUE;
			withalertscreen = FALSE;
			noalertscreen = FALSE;
		}
	}
	stage "Sellers"{
		startwaitforall = FALSE;
		startConditionStr = "";
		singleentry = FALSE;
		singleentrycontinuation = FALSE;
		timeouttype = always;
		timeout = TradingTime;
		program{
			table = subjects;
			do{
				IsBuyer = if(Player <= 4, 1, 0);
						Participate = 1 - IsBuyer;
			}
		}
		screen action{
			usesbg = TRUE;
			withalertscreen = FALSE;
			noalertscreen = FALSE;
			standardbox "You"{
				hasframe = TRUE;
				width = 30%;
				left = 0;
				cutleft = TRUE;
				buttonposition = BOTTOMRIGHT;
				buttonsequence = HORIZONTAL;
				item{
					label = "You are a seller.";
				}
				item{
					label = "Units traded";
					variable = UnitsTraded;
					format = "1";
					input = FALSE;
				}
				item{
					label = "Your next unit costs";
					variable = Costs[UnitsTraded + 1];
					format = "1";
					input = FALSE;
				}
				item{
					label = "Profit so far";
					variable = Profit;
					format = "1";
					input = FALSE;
				}
			}
			makecontractbox "Make an offer"{
				hasframe = TRUE;
				width = 40%;
				table = contracts;
				buttonposition = BOTTOMRIGHT;
				buttonsequence = HORIZONTAL;
				emptyallowed = FALSE;
				allemptyallowed = FALSE;
				numrecords = 1;
				tablelayout = VERTICAL;
				item{
					label = "Price";
					variable = Price;
					format = "1";
					input = TRUE;
					showdefault = FALSE;
					emptyallowed = FALSE;
					min = 0;
					max = MaxPrice;
				}
				button "Ask"{
					clearinputafterok = FALSE;
					norecordmadeorselected = FALSE;
					terminatestage = FALSE;
					donotterminatestage = FALSE;
					specialbuttoncolor = FALSE;
					buttoncolor = 0;
					checker{
						condition = :UnitsTraded < MaxUnits;
						message = "You have traded all your units.";
						yesButtonStr = "";
						noButtonStr = "OK";
					}
					checker{
						condition = contracts.count(Buyer == -1 & Seller > 0) == 0 | Price < contracts.minimum(Buyer == -1 & Seller > 0, Price);
						message = "Your ask must be lower than the best ask.";
						yesButtonStr = "";
						noButtonStr = "OK";
					}
					program{
						table = contracts;
						do{
							Seller = :Subject;
							Buyer = -1;
						}
					}
				}
			}
			selectcontractbox "Asks"{
				hasframe = TRUE;
				width = 30%;
				table = contracts;
				buttonposition = BOTTOMRIGHT;
				buttonsequence = HORIZONTAL;
				emptyallowed = FALSE;
				allemptyallowed = FALSE;
				condition = Buyer == -1 & Seller > 0;
				sortfields = "Price";
				tablelayout = LIST;
				scrollatstart = FALSE;
				scrollatEnd = FALSE;
				selectbest = FALSE;
				item{
					label = "Ask";
					variable = Price;
					format = "1";
					input = FALSE;
				}
			}
			selectcontractbox "Bids"{
				hasframe = TRUE;
				width = 30%;
				table = contracts;
				buttonposition = BOTTOMRIGHT;
				buttonsequence = HORIZONTAL;
				emptyallowed = FALSE;
				allemptyallowed = FALSE;
				condition = Seller == -1 & Buyer > 0;
				sortfields = "-Price";
				tablelayout = LIST;
				scrollatstart = FALSE;
				scrollatEnd = FALSE;
				selectbest = TRUE;
				item{
					label = "Bid";
					variable = Price;
					format = "1";
					input = FALSE;
				}
				button "Sell"{
					clearinputafterok = FALSE;
					norecordmadeorselected = FALSE;
					terminatestage = FALSE;
					donotterminatestage = FALSE;
					specialbuttoncolor = FALSE;
					buttoncolor = 0;
					checker{
						condition = :UnitsTraded < MaxUnits;
						message = "You have traded all your units.";
						yesButtonStr = "";
						noButtonStr = "OK";
					}
					program{
						table = contracts;
						do{
							Seller = :Subject;
									TradePrice = Price;
									subjects.do {
										if (Subject == :Buyer) {
											UnitsTraded = UnitsTraded + 1;
											Profit = Profit + Values[UnitsTraded] - :Price;
										}
										if (Subject == :Seller) {
											UnitsTraded = UnitsTraded + 1;
											Profit = Profit + :Price - Costs[UnitsTraded];
										}
									}
									// The traders' other offers are withdrawn.
									contracts.do {
										if (Seller == :Seller & Buyer == -1) {
											Buyer = -2;
										}
										if (Buyer == :Buyer & Seller == -1) {
											Seller = -2;
										}
									}
						}
					}
				}
			}
			selectcontractbox "Trades"{
				hasframe = TRUE;
				width = 30%;
				table = contracts;
				buttonposition = BOTTOMRIGHT;
				buttonsequence = HORIZONTAL;
				emptyallowed = FALSE;
				allemptyallowed = FALSE;
				condition = Buyer > 0 & Seller > 0;
				sortfields = "";
				tablelayout = LIST;
				scrollatstart = FALSE;
				scrollatEnd = FALSE;
				selectbest = FALSE;
				item{
					label = "Price";
					variable = TradePrice;
					format = "1";
					input = FALSE;
				}
			}
		}
		screen wait{
			usesbg = TRUE;
			withalertscreen = FALSE;
			noalertscreen = FALSE;
		}
	}
	stage "Results"{
		startwaitforall = TRUE;
		startConditionStr = "";
		singleentry = FALSE;
		singleentrycontinuation = FALSE;
		timeouttype = ifnoinput;
		timeout = 30;
		screen action{
			usesbg = TRUE;
			withalertscreen = FALSE;
			noalertscreen = FALSE;
			standardbox "Results"{
				hasframe = TRUE;
				buttonposition = BOTTOMRIGHT;
				buttonsequence = HORIZONTAL;
				item{
					label = "Units you traded";
					variable = UnitsTraded;
					format = "1";
					input = FALSE;
				}
				item{
					label = "Your payoff";
					variable = Profit;
					format = "1";
					input = FALSE;
				}
				button "Continue"{
					clearinputafterok = FALSE;
					norecordmadeorselected = FALSE;
					terminatestage = FALSE;
					donotterminatestage = FALSE;
					specialbuttoncolor = FALSE;
					buttoncolor = 0;
				}
			}
		}
		screen wait{
			usesbg = TRUE;
			withalertscreen = FALSE;
			noalertscreen = FALSE;
		}
	}
	roles{
		role "S 1"{
		}
		role "S 2"{
		}
		role "S 3"{
		}
		role "S 4"{
		}
		role "S 5"{
		}
		role "S 6"{
		}
		role "S 7"{
		}
		role "S 8"{
		}
	}
	period "1"{
		prompt = "";
		subject 1{
			name = "";
			group = 1;
			do{
				Player = 1;
			}
		}
		subject 2{
			name = "";
			group = 1;
			do{
				Player = 2;
			}
		}
		subject 3{
			name = "";
			group = 1;
			do{
				Player = 3;
			}
		}
		subject 4{
			name = "";
			group = 1;
			do{
				Player = 4;
			}
		}
		subject 5{
			name = "";
			group = 1;
			do{
				Player = 5;
			}
		}
		subject 6{
			name = "";
			group = 1;
			do{
				Player = 6;
			}
		}
		subject 7{
			name = "";
			group = 1;
			do{
				Player = 7;
			}
		}
		subject 8{
			name = "";
			group = 1;
			do{
				Player = 8;
			}
		}
	}
	period "2"{
		prompt = "";
		subject 1{
			name = "";
			group = 1;
			do{
				Player = 1;
			}
		}
		subject 2{
			name = "";
			group = 1;
			do{
				Player = 2;
			}
		}
		subject 3{
			name = "";
			group = 1;
			do{
				Player = 3;
			}
		}
		subject 4{
			name = "";
			group = 1;
			do{
				Player = 4;
			}
		}
		subject 5{
			name = "";
			group = 1;
			do{
				Player = 5;
			}
		}
		subject 6{
			name = "";
			group = 1;
			do{
				Player = 6;
			}
		}
		subject 7{
			name = "";
			group = 1;
			do{
				Player = 7;
			}
		}
		subject 8{
			name = "";
			group = 1;
			do{
				Player = 8;
			}
		}
	}
}