C ++“无法添加两个指针"，将硬编码的字符串添加到CString [英] C++ "cannot add two pointers", adding a hardcoded string to a CString

问题描述

当我尝试做这样的事情时，我经常会收到此错误

I get this error quite often when I try to do something like this

CString filePath = theApp->GetSystemPath() + "test.bmp";

编译器告诉我

error C2110: '+' : cannot add two pointers

但是，如果我将其更改为以下内容，则可以正常工作吗?

But if I change it to this below it works fine?

CString filePath = theApp->GetSystemPath();
filePath += "test.bmp";

函数GetSystemPath返回与其相关的LPCTSTR

The function GetSystemPath returns a LPCTSTR if that has anything to do with it

推荐答案

这与您要处理的对象类型有关.

This has to do with the types of objects that you are dealing with.

CString filePath = theApp->GetSystemPath() + "test.bmp";

上面的行正在尝试使用"test.bmp"或LPCTSTR + char []添加GetSystemPath()的类型；编译器不知道如何执行此操作，因为这两种类型的操作符均为no +运算符.

The line above is attempting to add the type of GetSystemPath() with "test.bmp" or an LPCTSTR + char[]; The compiler does not know how to do this because their is no + operator for these two types.

此方法起作用的原因:

filePath += "test.bmp";

是因为您正在执行CString + char [](char *); CString类的+运算符已重载以支持添加CString + char *.或者，这是在将加法运算符应用于两个CString对象之前，从char *构造CString的方法. LPCTSTR没有重载此运算符或未定义适当的构造函数.

Is because you are doing CString + char[] (char*); The CString class has the + operator overloaded to support adding CString + char*. Or alternatively which is constructing a CString from a char* prior to applying the addition operator on two CString objects. LPCTSTR does not have this operator overloaded or the proper constructors defined.

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