我有一项任务,要求我创建一个分配和释放内存的“堆”类。我相信我的代码工作,解决方案构建和运行正常,但我想确保我没有任何内存泄漏。我还需要添加一些代码来检查分配给堆的所需数量是否可用...如果有人要分配非常大的数量。如何检查堆上分配的内存是否可用,或者如果内存不足,是否可以为NULL。到目前为止,这是我的代码:
#include <iostream>
using namespace std;
class Heap{
public:
double* allocateMemory(int memorySize)
{
return new double[memorySize];
};
void deallocateMemory(double* dMemorySize)
{
delete[] dMemorySize;
};
};
int main()
{
Heap heap;
cout << "Enter the number of double elements that you want to allocate: " << endl;
int hMemory;
const int doubleByteSize = 8;
cin >> hMemory;
double *chunkNew = heap.allocateMemory(hMemory);
cout << "The amount of space you took up on the heap is: " <<
hMemory*doubleByteSize << " bytes" <<
starting at address: " << "\n" << &hMemory << endl;
heap.deallocateMemory(chunkNew);
system("pause");
return 0;
}
答案 0 :(得分:11)
没有必要事先检查,只是尝试分配内存,如果不能,则捕获异常。在这种情况下,它的类型为bad_alloc
。
#include <iostream>
#include <new> // included for std::bad_alloc
/**
* Allocates memory of size memorySize and returns pointer to it, or NULL if not enough memory.
*/
double* allocateMemory(int memorySize)
{
double* tReturn = NULL;
try
{
tReturn = new double[memorySize];
}
catch (bad_alloc& badAlloc)
{
cerr << "bad_alloc caught, not enough memory: " << badAlloc.what() << endl;
}
return tReturn;
};
务必防止双重释放内存。一种方法是通过引用将指针传递给deallocateMemory
,允许函数将指针值更改为NULL
,从而防止delete
两次指针的可能性
void deallocateMemory(double* &dMemorySize)
{
delete[] dMemorySize;
dMemorySize = NULL; // Make sure memory doesn't point to anything.
};
这可以防止以下问题:
double *chunkNew = heap.allocateMemory(hMemory);
heap.deallocateMemory(chunkNew);
heap.deallocateMemory(chunkNew); // chunkNew has been freed twice!