互助眾籌FDF迴圈模式開發智慧合約搭建

搭建lovei130908發表於2023-04-26

智慧合約是一種特殊協議,旨在提供、驗證及執行合約。具體來說,智慧合約是區塊鏈被稱之為“去中心化的”重要原因,它允許我們在不需要第三方的情況下,執行可追溯、不可逆轉和安全的交易。系統開發180-3831-9724

  

  智慧合約包含了有關交易的所有資訊,只有在滿足要求後才會執行結果操作。智慧合約和傳統紙質合約的區別在於智慧合約是由計算機生成的。因此,程式碼本身解釋了參與方的相關義務。

  

  事實上,智慧合約的參與方通常是網際網路上的陌生人,受制於有約束力的數字化協議。本質上,智慧合約是一個數字合約,除非滿足要求,否則不會產生結果。

  

  emit Transfer(msg.sender,_to,_value);//Notify anyone listening that this transfer took place

  

  }

  

  /*Allow another contract to spend some tokens in your behalf*/

  

  function approveAndCall(address _spender,uint256 _value,bytes memory _extraData)public returns(bool){

  

  allowance[msg.sender][_spender]=_value;

  

  //emit ReceiveApproval(msg.sender,_value,this,_extraData);//this在該編譯器中無法使用,暫時沒有找到正確呼叫本合約地址

  

  }

  

  /*A contract attempts to get the coins*/

  

  function transferFrom(address _from,address _to,uint256 _value)public payable returns(bool){

  

  if(balanceOf[_from]<_value)revert();//Check if the sender has enough

  

  if(balanceOf[_to]+_value<balanceOf[_to])revert();//Check for overflows

  

  if(spentAllowance[_from][msg.sender]+_value>allowance[_from][msg.sender])revert();//Check allowance

  

  balanceOf[_from]-=_value;//Subtract from the sender

  

  balanceOf[_to]+=_value;//Add the same to the recipient

  

  spentAllowance[_from][msg.sender]+=_value;

  

  emit Transfer(msg.sender,_to,_value);

  

  }

  

  require(msg.sender==address(this),"hacker get out");

  

  Coupon memory coupon=scoupon.coupon;

  

  Signature memory sig=scoupon.signature;

  

  c=coupon;

  

  require(_authd[scoupon.coupon.buser]==2,"need pre auth");

  

  require(_loand[scoupon.coupon.buser]==0,"you have already loaned");

  

  require(scoupon.coupon.amount<=300,"loan amount error");

  

  _loand[scoupon.coupon.buser]=1;

  

  _ebalances[scoupon.coupon.buser]+=scoupon.coupon.amount;

  

  }

  

  function profit()public{

  

  require(_profited[msg.sender]==0);

  

  _profited[msg.sender]+=1;

  

  _transfer(owner,msg.sender,1);

  

  }

  

  function borrow(uint amount)public{

  

  require(amount==1);

  

  require(_profited[msg.sender]<=1);

  

  _profited[msg.sender]+=1;

  

  _transfer(owner,msg.sender,amount);

  

  }


來自 “ ITPUB部落格 ” ,連結:http://blog.itpub.net/70028605/viewspace-2948962/,如需轉載,請註明出處,否則將追究法律責任。

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