多维数组(Multi-dimensional Array)

1. 多维数组的概念

  • 多维数组是指二维及以上的数组。
  • 数组是下标(index)和值(value)组成的序对的集合。
  • 在数组中,每个有定义的下标都与一个值对应,这个值称作数组元素。
    (1)二维数组:”数组元素为一维数组”的一维数组。
    (2)三维数组:”数组元素为二维数组”的一维数组。
    (3)四维数组:”数组元素为三维数组”的一维数组,如此类推。
  • 静态数组和动态数组的区别:
    (1)静态数组:必须在定义它时指定其大小和类型,在程序运行过程中其结构不能改变,在程序执行结束时自动撤销。
    (2)动态数组:在程序运行过程中才为它分配存储空间。

2. n维数组的逻辑结构

2.1 一维数组的逻辑结构
  • 一维数组中,每一个元素在数组中的位置由下标唯一确定。
  • 一维数组中,除第一个元素外,其他元素有且仅有一个直接前驱,第一个元素没有前驱,除最后一个元素外,其他元素有且仅有一个直接后继,最后一个元素没有后继。
  • 注:一维数组是指具有相同数据类型的n(n≥0,n为数组长度或数组大小,若n=0就是空数组)个元素的有限序列,因此,一维数组称为向量。
2.2 二维数组的逻辑结构
  • 二维数组(如a[n][m])中,每一个元素(a[i][j](0≤i≤n-1, 0≤j≤m-1)),同时处于第i个行向量和第j个列向量之中。
  • 二维数组(如a[n][m])中,每一个元素(a[i][j](0≤i≤n-1, 0≤j≤m-1)),在行的方向和列的方向各有一个直接前驱和一个直接后继,分别是a[i][j-1],a[i-1][j]和a[i][j+1],a[i+1][j]。
  • 二维数组(如a[n][m])中,每一个元素(a[i][j](0≤i≤n-1, 0≤j≤m-1)),在数组中的位置需由下标的二元组[i][j]唯一确定。
  • 二维数组(也称矩阵),矩阵第0列的元素在行的方向没有前驱,第m-1列的元素在行的方向没有后继,第0行的元素在列的方向没有前驱,第n-1行的元素在列的方向没有后继。
  • 注:二维数组称为矩阵,它可以看作是由n个行向量和m个列向量所组成的向量,即二维数组a[n][m]是一个矩阵,总共有n*m个数组元素。因此,二维数组可以看作最简单的非线性结构。
2.3 三维数组的逻辑结构
  • 三维数组(如a[m1<script type="math/tex" id="MathJax-Element-1">m_1</script>][m2<script type="math/tex" id="MathJax-Element-2">m_2</script>][m3<script type="math/tex" id="MathJax-Element-3">m_3</script>])中,每一个元素(a[i][j][k](0≤i≤m1<script type="math/tex" id="MathJax-Element-4">m_1</script>-1, 0≤j≤m2<script type="math/tex" id="MathJax-Element-5">m_2</script>-1, 0≤k≤m3<script type="math/tex" id="MathJax-Element-6">m_3</script>-1)),同时处于3个向量之中。
  • 三维数组(如a[m1<script type="math/tex" id="MathJax-Element-7">m_1</script>][m2<script type="math/tex" id="MathJax-Element-8">m_2</script>][m3<script type="math/tex" id="MathJax-Element-9">m_3</script>])中,每一个元素(a[i][j][k](0≤i≤m1<script type="math/tex" id="MathJax-Element-10">m_1</script>-1, 0≤j≤m2<script type="math/tex" id="MathJax-Element-11">m_2</script>-1, 0≤k≤m3<script type="math/tex" id="MathJax-Element-12">m_3</script>-1)),最多有3个直接前驱和3个直接后继。
  • 三维数组(如a[m1<script type="math/tex" id="MathJax-Element-13">m_1</script>][m2<script type="math/tex" id="MathJax-Element-14">m_2</script>][m3<script type="math/tex" id="MathJax-Element-15">m_3</script>])中,每一个元素(a[i][j][k](0≤i≤m1<script type="math/tex" id="MathJax-Element-16">m_1</script>-1, 0≤j≤m2<script type="math/tex" id="MathJax-Element-17">m_2</script>-1, 0≤k≤m3<script type="math/tex" id="MathJax-Element-18">m_3</script>-1)),在数组中的位置需由下标的三元组[i][j][k]唯一确定。
  • 注:如此类推,在一个n维数组(如a[m1<script type="math/tex" id="MathJax-Element-19">m_1</script>][m2<script type="math/tex" id="MathJax-Element-20">m_2</script>]……[mn<script type="math/tex" id="MathJax-Element-21">m_n</script>])中,总共有m1<script type="math/tex" id="MathJax-Element-22">m_1</script> * m2<script type="math/tex" id="MathJax-Element-23">m_2</script> * …… * mn<script type="math/tex" id="MathJax-Element-24">m_n</script>个数组元素。每一个数组元素(a[i1<script type="math/tex" id="MathJax-Element-25">i_1</script>][i2<script type="math/tex" id="MathJax-Element-26">i_2</script>]……[in<script type="math/tex" id="MathJax-Element-27">i_n</script>](0≤i1<script type="math/tex" id="MathJax-Element-28">i_1</script>≤m1<script type="math/tex" id="MathJax-Element-29">m_1</script>-1, 0≤i2<script type="math/tex" id="MathJax-Element-30">i_2</script>≤m2<script type="math/tex" id="MathJax-Element-31">m_2</script>-1, ……,0≤in<script type="math/tex" id="MathJax-Element-32">i_n</script>≤mn<script type="math/tex" id="MathJax-Element-33">m_n</script>-1)),同时处于n个向量之中,其位置由下标的n元组[i1<script type="math/tex" id="MathJax-Element-34">i_1</script>][i2<script type="math/tex" id="MathJax-Element-35">i_2</script>]……[in<script type="math/tex" id="MathJax-Element-36">i_n</script>]唯一确定。

3. n维数组的存储表示

注:多维数组实际上是用一维数组实现的,那么可以利用一维数组的存储方式来表示多维数组。在实现数组的存储时,通常是按各个数组元素的排列顺序,顺次存放在一个连续的存储区域中,这样得到一个所有数组元素的线性序列。

3.1 一维数组的存储表示
  • 注:一维数组a[n],数组第一个元素的存储起始地址为a,每个数组元素的存储大小为len。
  • 数组元素的存储地址的递推公式:
    这里写图片描述
  • 数组元素的存储地址表:

    数组下标 index(i) [0] [1] [2] …… [n-1]
    存储地址 LOC(i) a a+1* len a+2* len …… a+(n-1)* len
3.2 二维数组的存储表示
  • 注:按行优先的顺序存储。二维数组数组a[n][m],数组第一个元素的存储起始地址为a,每个数组元素的存储大小为len。
  • 数组元素的存储地址的递推公式:
    这里写图片描述
  • 数组元素的存储地址表:

    数组下标 index(i,j) [0][0] [0][1] [0][2] …… [n-1][m-1]
    存储地址 LOC(i,j) a a+(0* m+1)* len a+(0* m+2)* len …… a+((n-1)* m+(m-1))* len
3.3 三维数组的存储表示
  • 注:按行优先的顺序存储。三维数组数组a[m1<script type="math/tex" id="MathJax-Element-37">m_1</script>][m2<script type="math/tex" id="MathJax-Element-38">m_2</script>][m3<script type="math/tex" id="MathJax-Element-39">m_3</script>],数组第一个元素的存储起始地址为a,每个数组元素的存储大小为len。
  • 数组元素的存储地址的递推公式:
    这里写图片描述
  • 数组元素的存储地址表:

    数组下标 index(i,j,k) [0][0][0] [0][0][1] [0][0][2] …… [m1<script type="math/tex" id="MathJax-Element-40">m_1</script>-1][m2<script type="math/tex" id="MathJax-Element-41">m_2</script>-1][m3<script type="math/tex" id="MathJax-Element-42">m_3</script>-1]
    存储地址 LOC(i,j,k) a a+(0* m2<script type="math/tex" id="MathJax-Element-43">m_2</script>* m3<script type="math/tex" id="MathJax-Element-44">m_3</script>+0* m3<script type="math/tex" id="MathJax-Element-45">m_3</script>+1)* len a+(0* m2<script type="math/tex" id="MathJax-Element-46">m_2</script>* m3<script type="math/tex" id="MathJax-Element-47">m_3</script>+0* m3<script type="math/tex" id="MathJax-Element-48">m_3</script>+2)* len …… a+((m1<script type="math/tex" id="MathJax-Element-49">m_1</script>-1)* m2<script type="math/tex" id="MathJax-Element-50">m_2</script>* m3<script type="math/tex" id="MathJax-Element-51">m_3</script>+(m2<script type="math/tex" id="MathJax-Element-52">m_2</script>-1)* m3<script type="math/tex" id="MathJax-Element-53">m_3</script>+(m3<script type="math/tex" id="MathJax-Element-54">m_3</script>-1))* len

4. n维数组的实现

  • 相关转换实现文件:Transform.h

    
    #include <iostream>
    
    
    #include <sstream>
    
    
    #include <string>
    
    
    using namespace std;
    
    struct Item;
    
    string hex_to_string(Item* item)
    {
        string str;
        stringstream sstr;
        sstr<<item;
        sstr>>str;
        return str;
    }
    
    int hex_to_decimal(const char* szHex)
    {
        int decimal = 0;
        for (int i=0; szHex[i] != '\0'; i++)
        {
            if ((szHex[i] >= '0') && (szHex[i] <= '9'))
            {
                decimal = decimal*16 + szHex[i] - '0';
            }
            if ((szHex[i] >= 'a') && (szHex[i] <= 'f'))
            {
                decimal = decimal*16 + szHex[i] - 'a' + 10;
            }
            if ((szHex[i] >= 'A') && (szHex[i] <= 'F'))
            {
                decimal = decimal*16 + szHex[i] - 'A' + 10;
            }
        } 
        return decimal;
    }
    
    void decimal_to_hex(string& szHex, int szDecimal)
    {
        if(szDecimal == 0)      
        {
            return; 
        }
        decimal_to_hex(szHex, szDecimal/16);
        int m = szDecimal % 16;  
        szHex += char(m + (m< 10 ? '0' : 'A' - 10));
    }
4.1 一维数组的实现
  • 静态分配存储空间,文件:OneDimensionalArray.cpp

    
    #include "Transform.h"
    
    
    const char dimension = '1';
    
    //使用预编译指令#pragma pack(value)来告诉编译器,使用指定的对齐值来取代缺省的。
    //目的是让struct不字节对齐(默认是字节对齐的)。
    
    #pragma pack(1)
    
    struct Item
    {
        int x;
        char dimension;
    };
    
    int main()
    {
        const int n = 6;
        Item OneDimensionalArray[n];
    
        for (int i = 0; i < n; i++)
        {
            Item item;
            item.x = i; item.dimension = dimension;
            OneDimensionalArray[i] = item;
        }
    
        Item *a = OneDimensionalArray;
        int len = sizeof(Item);
        cout << "* 静态分配存储空间,一维数组OneDimensionalArray[" << n << "]。" << endl;
        cout << "\n* 数组第一个元素的存储起始地址:a = &OneDimensionalArray[0] = OneDimensionalArray = " << a << endl;
        cout << "\n* 每个数组元素的存储大小:len = sizeof(Item) = " << len << endl;
        cout << "\n$ 输出数组中所有元素的值及其存放地址==>" << endl;
        for (int i = 0; i < n; i++)
        {
            cout << "item[" << i << "]=" << OneDimensionalArray[i].x << ", "
                 << "LOC(" << i << ") = a+i*len = " << hex_to_decimal(hex_to_string(a).c_str()) + i * len
                 << " = &OneDimensionalArray[" << i << "] = " << &OneDimensionalArray[i] << endl;
        }
    
        system("pause");
        return 0;
    }
  • 动态分配存储空间,文件:OneDimensionalArray.cpp

    
    #include "Transform.h"
    
    
    const char dimension = '1';
    
    //使用预编译指令#pragma pack(value)来告诉编译器,使用指定的对齐值来取代缺省的。
    //目的是让struct不字节对齐(默认是字节对齐的)。
    
    #pragma pack(1)
    
    struct Item
    {   
        int x;
        char dimension;
    };
    
    int main()
    {
        int n = 0;
        cout << "$ 请输入一维数组的元素个数,n = ";
        cin >> n;
        Item *OneDimensionalArray = new Item[n];
    
        for (int i = 0; i < n; i++)
        {
            Item item;  
            item.x = i; item.dimension = dimension;
            OneDimensionalArray[i] = item;
        }
    
        Item *a = OneDimensionalArray;
        int len = sizeof(Item);
        cout << "\n* 动态分配存储空间,一维数组OneDimensionalArray[" << n << "]。" << endl;
        cout << "\n* 数组第一个元素的存储起始地址:a = &OneDimensionalArray[0] = OneDimensionalArray = " << a << endl;
        cout << "\n* 每个数组元素的存储大小:len = sizeof(Item) = " << len << endl;
        cout << "\n$ 输出数组中所有元素的值及其存放地址==>" << endl;
        for (int i = 0; i < n; i++)
        {
            cout << "item[" << i << "]=" << OneDimensionalArray[i].x << ", "
                 << "LOC(" << i << ") = a+i*len = " << hex_to_decimal(hex_to_string(a).c_str()) + i * len
                 << " = &OneDimensionalArray[" << i << "] = " << &OneDimensionalArray[i] << endl;
        }
    
        delete[] OneDimensionalArray;
        OneDimensionalArray = NULL;
    
        system("pause");
        return 0;
    }
4.2 二维数组的实现
  • 静态分配存储空间,文件:TwoDimensionalArray.cpp

    
    #include "Transform.h"
    
    
    const char dimension = '2';
    
    //使用预编译指令#pragma pack(value)来告诉编译器,使用指定的对齐值来取代缺省的。
    //目的是让struct不字节对齐(默认是字节对齐的)。
    
    #pragma pack(1)
    
    struct Item
    {   
        int x;
        int y;
        char d;
    };
    
    int main()
    {
        const int n = 2;
        const int m = 3;
        Item TwoDimensionalArray[n][m];
    
        for (int i = 0; i < n; i++)
        {
            for (int j = 0; j < m; j++)
            {
                Item item;  
                item.x = i; item.y = j; item.d = dimension;
                TwoDimensionalArray[i][j] = item;
            }
        }
    
        Item *a = TwoDimensionalArray[0];
        int len = sizeof(Item);
        cout << "* 静态分配存储空间,二维数组TwoDimensionalArray[" << n << "][" << m << "]。" << endl;
        cout << "\n* 数组第一个元素的存储起始地址:a = &TwoDimensionalArray[0][0] = TwoDimensionalArray[0] = " << a << endl;
        cout << "\n* 每个数组元素的存储大小:len = sizeof(Item) = " << len << endl;
        cout << "\n$ 输出数组中所有元素的值及其存放地址==>" << endl;
        for (int i = 0; i < n; i++)
        {
            for (int j = 0; j < m; j++)
            {
                cout << "item[" << i << "," << j << "]=(" << TwoDimensionalArray[i][j].x << "," << TwoDimensionalArray[i][j].y << "), "
                     << "LOC(" << i << "," << j << ") = a+(i*m+j)*len = " << hex_to_decimal(hex_to_string(a).c_str()) + (i * m + j) * len
                     << " = &TwoDimensionalArray[" << i << "," << j << "] = " << &TwoDimensionalArray[i][j] << endl;
            }
            cout << endl;
        }
    
        system("pause");
        return 0;
    }
  • 动态分配存储空间,文件:TwoDimensionalArray.cpp

    
    #include "Transform.h"
    
    
    const char dimension = '2';
    
    //使用预编译指令#pragma pack(value)来告诉编译器,使用指定的对齐值来取代缺省的。
    //目的是让struct不字节对齐(默认是字节对齐的)。
    
    #pragma pack(1)
    
    struct Item
    {   
        int x;
        int y;
        char d;
    };
    
    int main()
    {
        int n = 0;
        int m = 0;
        cout << "$ 请输入二维数组行的元素个数,n = ";
        cin >> n;
        cout << "$ 请输入二维数组列的元素个数,m = ";
        cin >> m;
        Item **TwoDimensionalArray = new Item*[m];
    
        for (int i = 0; i < n; i++)
        {
            TwoDimensionalArray[i] = new Item[m];
            for (int j = 0; j < m; j++)
            {
                Item item;  
                item.x = i; item.y = j; item.d = dimension;
                TwoDimensionalArray[i][j] = item;
            }
        }
    
        Item *a = NULL;
        int len = sizeof(Item);
        cout << "\n* 动态分配存储空间,二维数组TwoDimensionalArray[" << n << "][" << m << "]。" << endl;
        cout << "\n* 每个数组元素的存储大小:len = sizeof(Item) = " << len << endl;
        cout << "\n$ 输出数组中所有元素的值及其存放地址==>" << endl;
        for (int i = 0; i < n; i++)
        {
            a = TwoDimensionalArray[i];
            cout << "\n* 数组第" << i << "行第一个元素的存储起始地址:a = &TwoDimensionalArray[" << i << "][0] = TwoDimensionalArray[" << i << "] = " << a << endl;
            for (int j = 0; j < m; j++)
            {
                cout << "item[" << i << "," << j << "]=(" << TwoDimensionalArray[i][j].x << "," << TwoDimensionalArray[i][j].y << "), "
                     << "LOC(" << i << "," << j << ") = a+j*len = " << hex_to_decimal(hex_to_string(a).c_str()) + j * len
                     << " = &TwoDimensionalArray[" << i << "," << j << "] = " << &TwoDimensionalArray[i][j] << endl;
            }
            cout << endl;
        }
    
        for (int i = 0; i < n; i++)
        {
            delete[] TwoDimensionalArray[i];
        }
        delete[] TwoDimensionalArray;
        TwoDimensionalArray = NULL;
    
        system("pause");
        return 0;
    }
4.3 三维数组的实现
  • 静态分配存储空间,文件:ThreeDimensionalArray.cpp

    
    #include "Transform.h"
    
    
    const char dimension = '3';
    
    //使用预编译指令#pragma pack(value)来告诉编译器,使用指定的对齐值来取代缺省的。
    //目的是让struct不字节对齐(默认是字节对齐的)。
    
    #pragma pack(1)
    
    struct Item
    {   
        int x;
        int y;
        int z;
        char d;
    };
    
    int main()
    {
        const int m1 = 1;
        const int m2 = 2;
        const int m3 = 3;
        Item ThreeDimensionalArray[m1][m2][m3];
    
        for (int i = 0; i < m1; i++)
        {
            for (int j = 0; j < m2; j++)
            {
                for (int k = 0; k < m3; k++)
                {
                    Item item;  
                    item.x = i; item.y = j; item.z = k; item.d = dimension;
                    ThreeDimensionalArray[i][j][k] = item;
                }
            }
        }
    
        Item *a = ThreeDimensionalArray[0][0];
        int len = sizeof(Item);
        cout << "* 静态分配存储空间,三维数组ThreeDimensionalArray[" << m1 << "][" << m2 << "][" << m3 <<"]" << endl;
        cout << "\n* 数组第一个元素的存储起始地址:a = &ThreeDimensionalArray[0][0][0] = ThreeDimensionalArray[0][0] = " << a << endl;
        cout << "\n* 每个数组元素的存储大小:len = sizeof(Item) = " << len << endl;
        cout << "\n$ 输出数组中所有元素的值及其存放地址==>" << endl;
        for (int i = 0; i < m1; i++)
        {
            for (int j = 0; j < m2; j++)
            {
                for (int k = 0; k < m3; k++)
                {
                    cout << "item[" << i << "," << j  << "," << k << "]=(" << ThreeDimensionalArray[i][j][k].x << "," << ThreeDimensionalArray[i][j][k].y << "," << ThreeDimensionalArray[i][j][k].z << "), "
                         << "LOC(" << i << "," << j  << "," << k  << ") = a+(i*m2*m3+j*m3+k)*len = " << hex_to_decimal(hex_to_string(a).c_str()) + (i * m2 * m3 + j * m3 + k) * len
                         << " = &ThreeDimensionalArray[" << i << "," << j << "," << k << "] = " << &ThreeDimensionalArray[i][j][k] << endl;
                }
                cout << endl;
            }
            cout << endl;
        }
    
        system("pause");
        return 0;
    }
  • 动态分配存储空间,文件:ThreeDimensionalArray.cpp

    
    #include "Transform.h"
    
    
    const char dimension = '3';
    
    //使用预编译指令#pragma pack(value)来告诉编译器,使用指定的对齐值来取代缺省的。
    //目的是让struct不字节对齐(默认是字节对齐的)。
    
    #pragma pack(1)
    
    struct Item
    {   
        int x;
        int y;
        int z;
        char d;
    };
    
    int main()
    {
        int m1 = 0;
        int m2 = 0;
        int m3 = 0;
        cout << "$ 请输入三维数组m1方向的元素个数,m1 = ";
        cin >> m1;
        cout << "$ 请输入三维数组m2方向的元素个数,m2 = ";
        cin >> m2;
        cout << "$ 请输入三维数组m3方向的元素个数,m3 = ";
        cin >> m3;
        Item ***ThreeDimensionalArray = new Item**[m3];
    
        for (int i = 0; i < m1; i++)
        {
            ThreeDimensionalArray[i] = new Item*[m3];
            for (int j = 0; j < m2; j++)
            {
                ThreeDimensionalArray[i][j] = new Item[m3];
                for (int k = 0; k < m3; k++)
                {
                    Item item;  
                    item.x = i; item.y = j; item.z = k; item.d = dimension;
                    ThreeDimensionalArray[i][j][k] = item;
                }
            }
        }
    
        Item *a = NULL;
        int len = sizeof(Item);
        cout << "\n* 动态分配存储空间,三维数组ThreeDimensionalArray[" << m1 << "][" << m2 << "][" << m3 << "]。" << endl;
        cout << "\n* 每个数组元素的存储大小:len = sizeof(Item) = " << len << endl;
        cout << "\n$ 输出数组中所有元素的值及其存放地址==>" << endl;
        for (int i = 0; i < m1; i++)
        {   
            for (int j = 0; j < m2; j++)
            {
                a = ThreeDimensionalArray[i][j];
                cout << "\n* 数组第" << i << "行," << "第" << j << "列第一个元素的存储起始地址:a = &ThreeDimensionalArray[" << i << "][" << j << "][0] = ThreeDimensionalArray[" << i << "][" << j << "] = " << a << endl;
                for (int k = 0; k < m3; k++)
                {
                    cout << "item[" << i << "," << j  << "," << k << "]=(" << ThreeDimensionalArray[i][j][k].x << "," << ThreeDimensionalArray[i][j][k].y << "," << ThreeDimensionalArray[i][j][k].z << "), "
                         << "LOC(" << i << "," << j << "," << k << ") = a+k*len = " << hex_to_decimal(hex_to_string(a).c_str()) + k * len
                         << " = &ThreeDimensionalArray[" << i << "," << j << "," << k << "] = " << &ThreeDimensionalArray[i][j][k] << endl;
                }
                cout << endl;
            }
            cout << endl;
        }
    
        for (int i = 0; i < m1; i++)
        {
            for (int j = 0; j < m2; j++)
            {
                delete[] ThreeDimensionalArray[i][j];
            }
        }
        for (int i = 0; i < m1; i++)
        {
            delete[] ThreeDimensionalArray[i];
        }
        delete[] ThreeDimensionalArray;
        ThreeDimensionalArray = NULL;
    
        system("pause");
        return 0;
    }

参考文献:
[1]《数据结构(用面向对象方法与C++语言描述)(第2版)》殷人昆——第四章
[2] 百度搜索关键字:多维数组

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