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18_函数Function.md
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18_函数Function.md
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# 第18节:函数Function
- 可以返回多个数据,使用()包裹起来即可
- 可以对返回值命名,此时可以省略return关键字
- 可以解构返回值,对忽略的返回值直接使用逗号留空
- map无法作为参数或返回值
```js
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.13;
contract Function {
// Functions can return multiple values.
function returnMany()
public
pure
returns (
uint,
bool,
uint
)
{
return (1, true, 2);
}
// Return values can be named.
function named()
public
pure
returns (
uint x,
bool b,
uint y
)
{
return (1, true, 2);
}
// Return values can be assigned to their name.
// In this case the return statement can be omitted.
function assigned()
public
pure
returns (
uint x,
bool b,
uint y
)
{
x = 1;
b = true;
y = 2;
}
// Use destructuring assignment when calling another
// function that returns multiple values.
function destructuringAssignments()
public
pure
returns (
uint,
bool,
uint,
uint,
uint
)
{
(uint i, bool b, uint j) = returnMany();
// Values can be left out.
(uint x, , uint y) = (4, 5, 6);
return (i, b, j, x, y);
}
// Cannot use map for either input or output
// Can use array for input
function arrayInput(uint[] memory _arr) public {}
// Can use array for output
uint[] public arr;
function arrayOutput() public view returns (uint[] memory) {
return arr;
}
}
```