我已经有一段时间没有在 C++ 中使用模板了,但现在我真的需要它们。
我重现了我遇到的问题,但我不记得解决方案的实际进展情况。
#include <iostream>
#include <vector>
namespace problem {
template <typename T>
class data {
public:
inline data(T var) {
this->var = var;
}
private:
T var;
};
class storage {
public:
inline void push(problem::data<T> * data) {
this->VData.push_back(data);
}
private:
std::vector<problem::data<T> *> VData;
};
};
int main() {
problem::storage * testStorage = new problem::storage();
problem::data<int> * testData = new problem::data<int>(256);
testStorage->push(testData);
delete testData;
delete testStorage;
return 0;
}
g++ -Wall problem.cpp 给我以下错误。
problem.cpp:17:35: error: ‘T’ was not declared in this scope
problem.cpp:17:36: error: template argument 1 is invalid
problem.cpp:21:30: error: ‘T’ was not declared in this scope
problem.cpp:21:31: error: template argument 1 is invalid
problem.cpp:21:34: error: template argument 1 is invalid
problem.cpp:21:34: error: template argument 2 is invalid
problem.cpp: In member function ‘void problem::storage::push(int*)’:
problem.cpp:18:17: error: request for member ‘push_back’ in ‘((problem::storage*)this)->problem::storage::VData’, which is of non-class type ‘int’
problem.cpp: In function ‘int main()’:
problem.cpp:29:28: error: no matching function for call to ‘problem::storage::push(problem::data<int>*&)’
problem.cpp:29:28: note: candidate is:
problem.cpp:17:16: note: void problem::storage::push(int*)
problem.cpp:17:16: note: no known conversion for argument 1 from ‘problem::data<int>*’ to ‘int*’
我知道我可以使用成员模板,但我如何处理 vector ?
template <typename T>
inline void push(problem::data<T> * data) {
this->VData.push_back(data);
}
如果我使用成员模板,那么 vector 定义将留下这些错误。
problem.cpp:22:30: error: ‘T’ was not declared in this scope
problem.cpp:22:31: error: template argument 1 is invalid
problem.cpp:22:34: error: template argument 1 is invalid
problem.cpp:22:34: error: template argument 2 is invalid
problem.cpp: In member function ‘void problem::storage::push(problem::data<T>*)’:
problem.cpp:19:17: error: request for member ‘push_back’ in ‘this->.VData’, which is of non-class type ‘int’
最佳答案
如果你想要存储不止一种类型的值,你可以尝试这样的事情:http://ideone.com/jjuVq
class storage {
struct data_base {};
template <class K>
struct data: data_base {
data(K value): value_(value) {}
K value_;
};
typedef std::vector<data_base*> container_type;
public:
~storage() {
while(!this->VData.empty()) {
delete this->VData.back();
this->VData.pop_back();
}
}
template <class P>
inline void push(P v) {
this->VData.push_back(new data<P>(v));
}
template <class P>
P &get(int i) { return static_cast<data<P>*>(this->VData[i])->value_; }
private:
container_type VData;
};
或者只使用 boost::any 作为容器的值类型。
关于c++ - 将模板类作为参数传递给类方法并使用模板类作为 vector 模板类型,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/11560098/