释放分配给二维向量的内存

Question

I have the following 2 dimension vector:

std::vector<std::vector<int>> m_scoreVector; 

I try the following code to free the allocated memory. But, it does not work. Just a small portion of memory will be releases:

for (int k = 0; k < m_scoreVector.size(); ++k){     
    std::vector<int>().swap(m_scoreVector[k]);
    m_scoreVector[k].shrink_to_fit();   
    m_scoreVector[k].clear();
}

std::vector<std::vector<int>>().swap(m_scoreVector);
m_scoreVector.shrink_to_fit();
m_scoreVector.clear();

I am new to memory management. Please let me know how should I free the allocated memory for this vector. Thanks.

Answer 1

Vectors manage the memory for you. They will free the memory when they go out of scope. In general, if you don't allocate memory with new or malloc, you don't need to worry about freeing it either.

Answer 2

swap() and shrink_to_fit() are two ways to free vector memory,you can not use it together

try this code:

for (int k = 0; k < m_scoreVector.size(); ++k){     
    m_scoreVector[k].clear();
    m_scoreVector[k].shrink_to_fit();   
}
m_scoreVector.clear();
m_scoreVector.shrink_to_fit();