library, importing & transactions practice

Author: Jesus Najera

.DS_Store

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+pragma solidity ^0.4.9;
+
+contract Transaction {
+    // each contract has an ethereum address - it can be found with: address(this)
+
+    event SenderLogger(address);
+    event ValueLogger(uint);
+
+    address private owner;
+
+    modifier isOwner {
+        require(owner==msg.sender);
+        _;
+    }
+
+     modifier validValue {
+        require(msg.value >= 1);
+        _;
+    }
+
+    function Transaction() {
+        owner = msg.sender;
+    }
+
+    //payable is a modifier that can be added to any function
+    //payable is a reserved keyword that allows a contract to receive ether
+    // a contract can have exactly one unnamed function, it is default executed if contract is called w  no parms
+    function () payable isOwner validValue {
+        SenderLogger(msg.sender);
+        ValueLogger(msg.value);
+    }
+}

Transaction.sol

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+pragma solidity ^0.4.8;
+
+library IntExtended {
+
+    function decrement(uint _self) returns (uint) {
+        return _self-1;
+    }
+
+    function decrementByValue(uint _self, uint _value) returns (uint) {
+        return _self-_value;
+    }
+
+    function increment(uint _self) returns (uint) {
+        return _self+1;
+    }
+
+    function incrementByValue(uint _self, uint _value) returns (uint) {
+        return _self+_value;
+    }
+}

libraryImportingPractice/library.sol

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+pragma solidity ^0.4.8;
+
+import "browser/library.sol";
+
+contract testLibrary {
+    using IntExtended for uint;
+
+    function testDecrement(uint _base) returns (uint) {
+        return IntExtended.decrement(_base);
+    }
+
+    function testDecrementByValue(uint _base, uint _value) returns (uint) {
+        return _base.decrementByValue(_value);
+    }
+
+    function testIncrement(uint _base) returns (uint) {
+        return IntExtended.increment(_base);
+    }
+
+    function testIncrementByValue(uint _base, uint _value) returns (uint) {
+        return _base.incrementByValue(_value);
+    }
+}