C++使用模板清空容器

1、清空容器的模板函数（包括vector、list、deque等）

// 支持迭代器
template<typename T>
void clearContainer(T &arr)
{
	T::iterator it;
	for (it = arr.begin(); arr.end() != it; ) {
		auto p = *it;
		if (p) {
			delete p;
			p = nullptr;
		}
		
		it = arr.erase(it);
	} // end for
}

// 另一种写法
template<typename T>
void clearContainer2(T &arr)
{
	for (int i = 0; i < arr.size(); ++i) {
		auto p = arr[i];
		if (p) {
			delete p;
			p = nullptr;
		}
	} // end for

	arr.clear();
}

2、测试代码

#include <iostream>
#include <string>
#include <vector>
#include <list>
#include <deque>
#include <stack>
using namespace std;

void test1()
{
	vector<int *> vecData;
	list<int *> lstData;
	deque<int *> deqData;
	stack<int *> stackData;

	for (int i = 1; i < 5; ++i) {
		vecData.emplace_back(new int(i));
		lstData.emplace_back(new int(i));
		deqData.emplace_back(new int(i));
		stackData.emplace(new int(i));
	}

	clearContainer(vecData);
	clearContainer(lstData);
	clearContainer(deqData);
	//clearContainer(stackData); // stack不支持迭代器

	int len1 = vecData.size();
	int len2 = lstData.size();
	int len3 = deqData.size();
	int len4 = stackData.size();

	char *log = new char[1024];
	sprintf_s(log, 1024, "%d, %d, %d, %d", len1, len2, len3, len4);
	cout << string(log) << endl;

	delete [] log;
}

int _tmain(int argc, _TCHAR* argv[])
{
    test1();

	return 0;
}

3、运行结果

0, 0, 0, 4