隨著技術(shù)的不斷進步，智能手機的普及情況加深，移動互聯(lián)網(wǎng)的盈利模式不斷擴大和成熟，可以想象未來的移動互聯(lián)網(wǎng)市場前景更廣闊，規(guī)模也會逐漸超越傳統(tǒng)互聯(lián)網(wǎng)。移動互聯(lián)網(wǎng)引發(fā)的市場多元化，一方面讓原有的市場變得更加垂直縱深，一方面是讓大市場和小市場并存。當然傳統(tǒng)互聯(lián)網(wǎng)還是不可被取代，傳統(tǒng)互聯(lián)網(wǎng)如果能與移動互聯(lián)網(wǎng)很好地融合，移動互聯(lián)網(wǎng)帶動傳統(tǒng)互聯(lián)網(wǎng)發(fā)展，將會是一個美好的愿景。

function div(uint256 a, uint256 b) internal constant returns (uint256) {

? ? // assert(b > 0); // Solidity automatically throws when dividing by 0

? ? uint256 c = a / b;

? ? // assert(a == b * c + a % b); // There is no case in which this doesn't hold

? ? return c;

? }

? function sub(uint256 a, uint256 b) internal constant returns (uint256) {

? ? assert(b <= a);

? ? return a - b;

? }

? function add(uint256 a, uint256 b) internal constant returns (uint256) {

? ? uint256 c = a + b;

? ? assert(c >= a);

? ? return c;

? }開發(fā)流程及源碼I59系統(tǒng)2OO7開發(fā)3O69

? function toUINT112(uint256 a) internal constant returns(uint112) {

? ? assert(uint112(a) == a);

? ? return uint112(a);

? }

? function toUINT120(uint256 a) internal constant returns(uint120) {

? ? assert(uint120(a) == a);

? ? return uint120(a);

? }

? function toUINT128(uint256 a) internal constant returns(uint128) {

? ? assert(uint128(a) == a);

? ? return uint128(a);

? }

}規(guī)則及案例：yy625019

// Abstract contract for the full ERC 20 Token standard

// https://github.com/ethereum/EIPs/issues/20

contract Token {

? ? /* This is a slight change to the ERC20 base standard.

? ? function totalSupply() constant returns (uint256 supply);

? ? is replaced with:

? ? uint256 public totalSupply;

? ? This automatically creates a getter function for the totalSupply.

? ? This is moved to the base contract since public getter functions are not

? ? currently recognised as an implementation of the matching abstract

? ? function by the compiler.

? ? */

? ? /// total amount of tokens

? ? //uint256 public totalSupply;

? ? function totalSupply() constant returns (uint256 supply);

? ? /// @param _owner The address from which the balance will be retrieved

? ? /// @return The balance

? ? function balanceOf(address _owner) constant returns (uint256 balance);

? ? /// @notice send `_value` token to `_to` from `msg.sender`

? ? /// @param _to The address of the recipient

? ? /// @param _value The amount of token to be transferred

? ? /// @return Whether the transfer was successful or not

? ? function transfer(address _to, uint256 _value) returns (bool success);

? ? /// @notice send `_value` token to `_to` from `_from` on the condition it is approved by `_from`

? ? /// @param _from The address of the sender

? ? /// @param _to The address of the recipient

? ? /// @param _value The amount of token to be transferred

? ? /// @return Whether the transfer was successful or not

? ? function transferFrom(address _from, address _to, uint256 _value) returns (bool success);

? ? /// @notice `msg.sender` approves `_addr` to spend `_value` tokens

? ? /// @param _spender The address of the account able to transfer the tokens

? ? /// @param _value The amount of wei to be approved for transfer

? ? /// @return Whether the approval was successful or not

? ? function approve(address _spender, uint256 _value) returns (bool success);

? ? /// @param _owner The address of the account owning tokens

? ? /// @param _spender The address of the account able to transfer the tokens

? ? /// @return Amount of remaining tokens allowed to spent

? ? function allowance(address _owner, address _spender) constant returns (uint256 remaining);

? ? event Transfer(address indexed _from, address indexed _to, uint256 _value);

? ? event Approval(address indexed _owner, address indexed _spender, uint256 _value);

}

/// VEN token, ERC20 compliant

contract VEN is Token, Owned {

? ? using SafeMath for uint256;

? ? string public constant name? ? = "VeChain Token";? //The Token's name

? ? uint8 public constant decimals = 18;? ? ? ? ? ? ? ?//Number of decimals of the smallest unit

? ? string public constant symbol? = "VEN";? ? ? ? ? ? //An identifier? ??

? ? // packed to 256bit to save gas usage.

? ? struct Supplies {

? ? ? ? // uint128's max value is about 3e38.

? ? ? ? // it's enough to present amount of tokens

? ? ? ? uint128 total;

? ? ? ? uint128 rawTokens;

? ? }