怎么会发生这种情况? [英] How is it that this can happen?
问题描述
他们是电子表格/ *然后是* / CreateObject(){} //我很困惑这是合法的。
这是什么意思?
Their is a Spreadsheet /*then a*/ CreateObject(){} //I am confused how this is legal.
What does it mean?
Spreadsheet CreateObject() { return Spreadsheet(3, 2); };
int main(){ }
我尝试了什么:
他们是电子表格/ *然后是* / CreateObject(){} //我很困惑这是合法的。
这是什么意思?
Spreadsheet CreateObject(){return Spreadsheet(3,2); };
int main(){}
What I have tried:
Their is a Spreadsheet /*then a*/ CreateObject(){} //I am confused how this is legal.
What does it mean?
Spreadsheet CreateObject() { return Spreadsheet(3, 2); };
int main(){ }
推荐答案
这是一个格式为对象函数体<的函数实现/ code>喜欢
This a function implementation in the formatObject function body
like
int func() { return 0; };
对象不是一个好主意,因为Spreadsheet对象是在函数体中分配的,而副本是在栈上分配的。
更好是使用对象指针:
It is not a good idea for objects because the Spreadsheet object is allocated in the function body and the a copy on the stack.
Better is to work with object pointers:
Spreadsheet* CreateObject() { return new Spreadsheet(3, 2); };
你不会写入函数。你需要在某处删除电子表格*。
Which you wont write into a function. And you need to delete the Spreadsheet* somewhere.
这是完全合法的(和惯用的) C ++
代码,因为 RVO [ ^ ]通常没有性能损失。
That is perfectly legal (and idiomatic) C++
code, due to RVO[^] there is usually no performance loss.
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