获取向量的字节大小 [英] Getting the size in bytes of a vector

问题描述

很抱歉，这个简单而愚蠢的问题，但我找不到它。

Sorry for this maybe simple and stupid question but I couldn't find it anywhere.

我只是不知道如何获取a的大小（以字节为单位）

I just don't know how to get the size in bytes of a std::vector.

std::vector<int>MyVector;   
/* This will print 24 on my system*/   
std::cout << "Size of  my vector:\t" << sizeof(MyVector) << std::endl;

for(int i = 0; i < 1000; i++)
   MyVector.push_back(i);

/* This will still print 24...*/    
std::cout << "Size of  my vector:\t" << sizeof(MyVector) << std::endl;

那么我如何获得向量的大小？也许通过将24（向量大小）乘以项目数？

So how do I get the size of a vector?! Maybe by multiplying 24 (vector size) by the number of items?

推荐答案

Vector将其元素存储在内部分配的内存数组中。您可以这样做：

Vector stores its elements in an internally-allocated memory array. You can do this:

sizeof(std::vector<int>) + (sizeof(int) * MyVector.size())

这将为您提供向量结构本身的大小以及其中所有int的大小它，但是它可能不包括您的内存分配器可能施加的任何少量开销。我不确定是否存在一种独立于平台的方式。

This will give you the size of the vector structure itself plus the size of all the ints in it, but it may not include whatever small overhead your memory allocator may impose. I'm not sure there's a platform-independent way to include that.

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