问题描述
我需要动态分配大小在运行时给定的一维和二维数组.
I need to dynamically allocate 1-D and 2-D arrays whose sizes are given at run-time.
我设法发现"了 std::vector 并且我认为它符合我的目的，但我想问一下我写的内容是否正确和/或可以改进.
I managed to "discover" std::vector and I think it fits my purposes, but I would like to ask whether what I've written is correct and/or can be improved.
这就是我正在做的:
#include <vector>
typedef std::vector< std::vector<double> > matrix;
//... various code and other stuff
std::vector<double> *name = new std::vector<double> (size);
matrix *name2 = new matrix(sizeX, std::vector<double>(sizeY));
推荐答案
如您所见，在运行时给定维度时需要动态分配数组.
Dynamically allocating arrays is required when your dimensions are given at runtime, as you've discovered.
然而，std::vector 已经是这个过程的wrapper，所以动态分配向量就像一个双重肯定.这是多余的.
However, std::vector is already a wrapper around this process, so dynamically allocating vectors is like a double positive. It's redundant.
直接写(C++98):
Just write (C++98):
#include <vector>
typedef std::vector< std::vector<double> > matrix;
matrix name(sizeX, std::vector<double>(sizeY));
或(C++11 及更高版本):
or (C++11 and later):
#include <vector>
using matrix = std::vector<std::vector<double>>;
matrix name(sizeX, std::vector<double>(sizeY));
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