C++ C+中的动态二维数组+；作为参数

我有一个使用动态规划求解问题的二维双精度数组。我想做的如下（f是对变量“size”进行操作并返回int的任何函数）：

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<>但是，这个代码显然是java和C++的混搭。如何在C++中实现这一点？

高度推荐使用向量作为动态数组的替代。向量在java中有坏名声，但是C++中它们是一条路。演示“A”C++实现这一方法，同时使用“新”的分配和向量。警告：与java不同，C++中的原始数组将要求您跟踪数组大小；所有内部数组也是如此

#include <iostream>
#include <vector>

class Test{
private:
    double **myArray;//Primitive 2d array; suggest using 2d vector.
    std::vector<std::vector<double>> myVector;//Alternative vector.
    std::vector<int> col;//Using vector for myArray sizes; where sizes = inner array size.
    int size;//Required with primitive dynamic array; size of array.
public:
    Test(){
        myArray = 0;//c++ initialization before reading; safety.
        size = 0;//c++ "" "" ""
    }
    ~Test(){
        flushArray();//Flush all data on destructor.
    }
    void flushArray(){//Empties 2d array and set it to 0.
        //Flush of primitive 2d array.
        for(int i = 0; i < size; ++i) {//Needs to delete every new data created
            delete []myArray[i];//Freeing memory for inner node.
        }
        delete []myArray;//Freeing memory for outer node.
        myArray = 0;//Setting pointer to 0;
        size = 0;//Setting size to 0;
        col.clear();//Flush for column vector: easy.

        //vector is self maintained and will clear itself on destructor; exception: "new" DATA.
    }
    void myFunction(int size) {
        if(this->size != 0) {//If there is already data...
            flushArray();//Flush Array;
        }
        this->size = size;//Require size to free during next call.
        myArray = new double*[size];//Create new array of nothings with a size of "size".
        for(int i = 0; i < size; ++i) {
            //Traversing through array and adding an array of doubles.
            myArray[i] = new double[f(size,false)];//New DATA can be implicit
        }
    }
    void otherFunction(int size) {
        myVector.clear();//Flush Vector;
        myVector.resize(size);//Automated dynamic sizing
        for(auto it = myVector.begin(); it != myVector.end(); ++it) {
            it->resize(f(size,true));
        }
    }
    int f(int size, bool isVector) {
        //.., do something.
        if(isVector) {
            return size;//Whatever int you were meant to return.
        }
        //Keep track of cols, maybe they'll vary
        col.push_back(size);//it might be (size+i)... Required for dynamic array.
        return col.back();//Return the intended size.
    }
    void printArraySize() {
        for(int i = 0; i < size; ++i) {
            std::cout<<"myArray["<<i<<"] has "<<col[i]<<" elements."<<std::endl;
        }
    }
    void printVectorSize() {
        //Using a counter, chose to use primitive for-loop.
        for(int i = 0; i < myVector.size(); ++i) {
            std::cout<<"myVector["<<i<<"] has "<<myVector[i].size()<<" elements. "<<std::endl;
        }
    }
};
int main()
{
    Test test;

    test.myFuntion(10);
    test.otherFunction(10);

    test.printArraySize();
    test.printVectorSize();

    return 0;
}

基本上是向量：你的数据，它们的大小和寿命是为你管理的；指向“新”数据的指针的异常向量。而在基本的动态数组中，您必须跟踪数组大小（所有数组），并在处理完后删除数据/数组

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编辑：小拼写检查.< /P>可变长度数组无效C++。您的编译器可能支持将它们作为扩展。您希望在此处使用

std:：vector

而不是

double[][]

。。。如果需要传递一个子集，则传递整个向量以及4个整数（rowstart、rowend、colstart、colend）或。。。双**myArr，int w，int h）自双myArr[大小][f（大小）]；必须动态分配编写一个简单的矩阵类，如下所示：

#include <iostream>
#include <vector>

class Test{
private:
    double **myArray;//Primitive 2d array; suggest using 2d vector.
    std::vector<std::vector<double>> myVector;//Alternative vector.
    std::vector<int> col;//Using vector for myArray sizes; where sizes = inner array size.
    int size;//Required with primitive dynamic array; size of array.
public:
    Test(){
        myArray = 0;//c++ initialization before reading; safety.
        size = 0;//c++ "" "" ""
    }
    ~Test(){
        flushArray();//Flush all data on destructor.
    }
    void flushArray(){//Empties 2d array and set it to 0.
        //Flush of primitive 2d array.
        for(int i = 0; i < size; ++i) {//Needs to delete every new data created
            delete []myArray[i];//Freeing memory for inner node.
        }
        delete []myArray;//Freeing memory for outer node.
        myArray = 0;//Setting pointer to 0;
        size = 0;//Setting size to 0;
        col.clear();//Flush for column vector: easy.

        //vector is self maintained and will clear itself on destructor; exception: "new" DATA.
    }
    void myFunction(int size) {
        if(this->size != 0) {//If there is already data...
            flushArray();//Flush Array;
        }
        this->size = size;//Require size to free during next call.
        myArray = new double*[size];//Create new array of nothings with a size of "size".
        for(int i = 0; i < size; ++i) {
            //Traversing through array and adding an array of doubles.
            myArray[i] = new double[f(size,false)];//New DATA can be implicit
        }
    }
    void otherFunction(int size) {
        myVector.clear();//Flush Vector;
        myVector.resize(size);//Automated dynamic sizing
        for(auto it = myVector.begin(); it != myVector.end(); ++it) {
            it->resize(f(size,true));
        }
    }
    int f(int size, bool isVector) {
        //.., do something.
        if(isVector) {
            return size;//Whatever int you were meant to return.
        }
        //Keep track of cols, maybe they'll vary
        col.push_back(size);//it might be (size+i)... Required for dynamic array.
        return col.back();//Return the intended size.
    }
    void printArraySize() {
        for(int i = 0; i < size; ++i) {
            std::cout<<"myArray["<<i<<"] has "<<col[i]<<" elements."<<std::endl;
        }
    }
    void printVectorSize() {
        //Using a counter, chose to use primitive for-loop.
        for(int i = 0; i < myVector.size(); ++i) {
            std::cout<<"myVector["<<i<<"] has "<<myVector[i].size()<<" elements. "<<std::endl;
        }
    }
};
int main()
{
    Test test;

    test.myFuntion(10);
    test.otherFunction(10);

    test.printArraySize();
    test.printVectorSize();

    return 0;
}

myArray[0] has 10 elements.  
myArray[1] has 10 elements.  
myArray[2] has 10 elements.  
myArray[3] has 10 elements.  
myArray[4] has 10 elements.  
myArray[5] has 10 elements.  
myArray[6] has 10 elements.  
myArray[7] has 10 elements.  
myArray[8] has 10 elements.  
myArray[9] has 10 elements.  
myVector[0] has 10 elements.  
myVector[1] has 10 elements.  
myVector[2] has 10 elements.  
myVector[3] has 10 elements.  
myVector[4] has 10 elements.  
myVector[5] has 10 elements.  
myVector[6] has 10 elements.  
myVector[7] has 10 elements.  
myVector[8] has 10 elements.  
myVector[9] has 10 elements.  

Process returned 0 (0x0)   execution time : 0.011 s  
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