无法在 xcode ios 项目中声明 C++ 向量

Can't declare C++ vector in xcode ios project

提问by Luchian Grigore

I'm trying to use a vector in a C++ class with xcode but it's giving me errors. The file has the .mmextension that is required for C++ files.

我试图在带有 xcode 的 C++ 类中使用向量，但它给了我错误。该文件具有.mmC++ 文件所需的扩展名。

This is my code:

这是我的代码：

class Synth{

private:

    int bpm;
    std::vector<Note> notesList;

public:

};

It's giving me these two errors:

它给了我这两个错误：

• error: Semantic Issue: Use of undeclared identifier 'std'
• error: Parse Issue: Expected member name or ';' after declaration specifiers

• 错误：语义问题：使用未声明的标识符“std”
• 错误：解析问题：预期的成员名称或“；” 声明说明符后

I also tried with using namespace std;on top but that made no difference. Any ideas what could be causing this?

我也试过using namespace std;在上面，但这没有什么区别。任何想法可能导致这种情况？

回答by Luchian Grigore

Yes, you need to include the header:

是的，您需要包含标题：

 #include <vector>

Don't use using namespace stdin a header file, rather keep your code as it is, with the explicit qualifier: std::vector.

不要using namespace std在头文件中使用，而是使用显式限定符保持代码原样：std::vector。