以太坊solidity编程常见错误（不定期更新）

1、报错：

Expected token Semicolon got 'eth_compileSolidity' funtion setFunder(uint _u,uint _amount){

解决：

funtion关键字错了，需要用function；

2、报错：

Variable is declared as a storage pointer. Use an explicit "storage" keyword to silence this warning. Funder f = funders[_u]; ^------^

解决：

Funder f，定义指针需要加关键字storage ；修改为Funder storage f = funders[_u];

3、报错：

Invoking events without "emit" prefix is deprecated. e("newFunder",_add,_amount); ^-------------------------^

解决：

调用事件需要在前面加上emit关键字，修改为emit e("newFunder",_add,_amount);

4、报错：

No visibility specified. Defaulting to "public". function newFunder(address _add,uint _amount) returns (uint){ ^ (Relevant source part starts here and spans across multiple lines).

解决：

定义函数必须加上public关键字，修改为function newFunder(address _add,uint _amount) public returns (uint){

5、报错：

"msg.gas" has been deprecated in favor of "gasleft()" uint public _gas = msg.gas; ^-----^

解决：msg.gas已经被gasleft()替换了。修改为uint public _gas = gasleft();

6、报错：

"throw" is deprecated in favour of "revert()", "require()" and "assert()". throw ;

解决：solidity已经不支持thorw了，需要使用require，用法require()

throw 写法：

if(msg.sender !=chairperson ||voters[_voter].voted ){

throw ;

}

require写法：

require(msg.sender !=chairperson ||voters[_voter].voted);

7、报错：

This declaration shadows an existing declaration. Voter delegate = voters[to]; ^------------^

解决：变量重复定义，变量名和函数名不能相同。

8、报错：

error: Function state mutability can be restricted to pure

解决：以前版本是可以不指定类型internal pure(外部不可调用)，public pure(外部可调用)(如不指定表示函数为可变行，需要限制)

9、报错：

"sha3" has been deprecated in favour of "keccak256"
解决：sha3已经替换为keccak256