未分配释放的指针(删除数组中的一个元素) [英] pointer being freed was not allocated(delete one element in an array)

问题描述

我是oop的初学者，这是我的问题

I am a beginner of oop, here is my question

int main(){
        int *p = new int[3];
        p[0] = 1;
        p[1] = 2;
        p[2] = 3;
        int* q = p;
        p++;  //here!
        delete p;
}

和

int main(){
        int *p = new int[3];
        p[0] = 1;
        p[1] = 2;
        p[2] = 3;
        int* q = p + 1;
        p++;  //here!
        delete p;
}

发生错误:释放的指针未分配 但 和

got bugs: pointer being freed was not allocated but and

int main(){
        int *p = new int[3];
        p[0] = 1;
        p[1] = 2;
        p[2] = 3;
        int* q = p + 1;
        delete p;
}

似乎很好！ 我想删除此数组中的一个元素.有人可以告诉我该错误的原因吗?

seems fine! I want to delete one element in this array. Can someone tell me the reason for the bug?

推荐答案

内存以连续的块分配，并且必须以相同的方式返回.最好假设您的内存块带有一个小的前缀，分配器使用它来确定它的来源和大小.

Memory is allocated in contiguous blocks, and must be returned in the same way. It is best to assume that your memory block comes with a small prefix that the allocator uses to determine where it came from and how large it was.

此外，新建"数组时，必须使用"delete []"将其释放.

Also, when you "new" an array, you must use "delete []" to release it.

thing* thingArray = new thing[64];

...

delete [] thingArray;

如果您尝试主动管理元素数组，则可能需要调查 std :: vector .

If you are trying to actively manage the array of elements, you may want to investigate a std::vector instead.

#include <vector>

std::vector<int> v;
v.push_back(10);
v.push_back(20);
v.push_back(30);
// v.size() is now 3 (num elements)
v.erase(v.begin()); // remove the first integer.
// v now "looks" like { 20, 30 }
// v.size() is now 2, not 3.

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