reorganize examples into folder

contracts/examples/BadArrayUse.sol

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+import '../PullPaymentCapable.sol';
+
+// UNSAFE CODE, DO NOT USE!
+
+contract BadArrayUse is PullPaymentCapable {
+  address[] employees;
+
+  function payBonus() {
+    for (var i = 0; i < employees.length; i++) {
+			address employee = employees[i];
+			uint bonus = calculateBonus(employee);
+    	asyncSend(employee, bonus);
+    }
+  }
+
+	function calculateBonus(address employee) returns (uint) {
+    // some expensive computation...
+  }
+
+}

contracts/examples/BadFailEarly.sol

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+// UNSAFE CODE, DO NOT USE!
+
+contract BadFailEarly {
+
+  uint constant DEFAULT_SALARY = 50000;
+  mapping(string => uint) nameToSalary;
+
+  function getSalary(string name) constant returns (uint) {
+    if (bytes(name).length != 0 && nameToSalary[name] != 0) {
+      return nameToSalary[name];
+    } else {
+      return DEFAULT_SALARY;
+    }
+  }
+}

contracts/examples/BadPushPayments.sol

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+// UNSAFE CODE, DO NOT USE!
+
+contract BadPushPayments {
+
+	address highestBidder;
+	uint highestBid;
+
+	function bid() {
+		if (msg.value < highestBid) throw;
+
+		if (highestBidder != 0) {
+      // return bid to previous winner
+			if (!highestBidder.send(highestBid)) {
+        throw;
+      }
+		}
+
+	  highestBidder = msg.sender;
+	  highestBid = msg.value;
+	}
+}

contracts/examples/GoodArrayUse.sol

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+import '../PullPaymentCapable.sol';
+
+contract GoodArrayUse is PullPaymentCapable {
+  address[] employees;
+  mapping(address => uint) bonuses;
+
+  function payBonus() {
+    for (uint i = 0; i < employees.length; i++) {
+			address employee = employees[i];
+			uint bonus = bonuses[employee];
+    	asyncSend(employee, bonus);
+    }
+  }
+
+	function calculateBonus(address employee) returns (uint) {
+    uint bonus = 0;
+    // some expensive computation...
+    bonuses[employee] = bonus;
+  }
+
+}

contracts/examples/GoodFailEarly.sol

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+contract GoodFailEarly {
+
+  uint constant DEFAULT_SALARY = 50000;
+  mapping(string => uint) nameToSalary;
+
+  function getSalary(string name) constant returns (uint) {
+    if (bytes(name).length == 0) throw;
+    if (nameToSalary[name] == 0) throw;
+
+    return nameToSalary[name];
+  }
+}

contracts/examples/GoodPullPayments.sol

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+contract GoodPullPayments {
+  address highestBidder;
+  uint highestBid;
+  mapping(address => uint) refunds;
+
+  function bid() external {
+    if (msg.value < highestBid) throw;
+
+    if (highestBidder != 0) {
+      refunds[highestBidder] += highestBid;
+    }
+
+    highestBidder = msg.sender;
+    highestBid = msg.value;
+  }
+
+  function withdrawBid() external {
+    uint refund = refunds[msg.sender];
+    refunds[msg.sender] = 0;
+    if (!msg.sender.send(refund)) {
+      refunds[msg.sender] = refund;
+    }
+  }
+}

contracts/examples/PullPaymentBid.sol

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+import '../PullPaymentCapable.sol';
+
+contract PullPaymentBid is PullPaymentCapable {
+  address public highestBidder;
+  uint public highestBid;
+  
+  function bid() external {
+    if (msg.value <= highestBid) throw;
+    
+    if (highestBidder != 0) {
+      asyncSend(highestBidder, highestBid);
+    }
+    highestBidder = msg.sender;
+    highestBid = msg.value;
+  }
+}