C++ 如何删除C++中的char *？
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How to delete char * in c++?
提问by karthik
In my application, I create a char*like this:
在我的应用程序中，我创建了一个char*这样的：
class sample
{
public:
char *thread;
};
sample::sample()
{
thread = new char[10];
}
sample::~sample()
{
delete []thread;
}
Am I doing the right thing in the code?
我在代码中做对了吗？
回答by Fred Larson
If you have []after your new, you need []after your delete. Your code looks correct.
如果你有你的[]后new，你需要[]后你的delete。您的代码看起来正确。
回答by karthik
List of points to be noted:
需要注意的点列表：
1) You need to allocate room for n characters, where n is the number of characters in the string, plus the room for the trailing null byte.
1) 您需要为 n 个字符分配空间，其中 n 是字符串中的字符数，加上尾随空字节的空间。
2) You then changed the thread to point to a different string. So you have to use delete[]function for the variable you are created using new[].
2) 然后将线程更改为指向不同的字符串。因此，您必须为使用delete[]创建的变量使用函数new[]。
But why are you fooling around with newand deletefor character data? Why not just use std::string, instead of 'C' functions? It's amazing why so many don't do the easiest thing:
但是，为什么你鬼混与new和delete字符数据？为什么不直接使用std::string, 而不是 'C' 函数？令人惊讶的是，为什么这么多人不做最简单的事情：
#include <cstdio>
#include <string>
int countWords(const char *p);
int main(int argc, char *argv[])
{
std::string pString = "The Quick Brown Fox!";
int numWords1 = countWords(pString.c_str());
printf("\n\n%d words are in the string %s", numWords1, pString.c_str());
int numWords2 = countWords(argv[1]);
printf("\n%d words are in the string %s", numWords2, argv[1]);
}
No need for new[], delete[], strcpy(), etc.
无需new[]，delete[]，strcpy()等。
Use strlen(). Better yet, don't use char*and use std::stringfor string data.
使用strlen(). 更好的是，不要使用char*和std::string用于字符串数据。
回答by GManNickG
It's "right"*, but it's very wrong.
这是“正确的”*，但这是非常错误的。
You should not use new[], but instead use std::vector<char>or std::string. Even if you weren't doing that, you need to respect the rule of three, or your class is broken.
您不应使用new[]，而应使用std::vector<char>或std::string。即使你没有这样做，你也需要尊重三原则，否则你的班级就被打破了。
*Assuming you meant new char[10]. Also, more orthodox is delete[] thread.
*假设你的意思是new char[10]. 此外，更正统的是delete[] thread。
回答by Jerry Coffin
Though it has nothing to do with the memory management, there is one other point to keep in mind. If you're going to define sample::sampleand sample::~sample, you first have to declare them, so your class definition should look something like this:
尽管它与内存管理无关，但还有一点需要牢记。如果要定义sample::sampleand sample::~sample，首先必须声明它们，因此您的类定义应如下所示：
class sample
{
public:
char *thread;
sample();
~sample();
};
As @GMan said, though, you really shouldn't be doing this at all...
不过，正如@GMan 所说，你真的不应该这样做......
