C/C++实现矩阵各种运算

程序很简单，重要的是二维指针的动态分配内存

type **Matrix ;//row为行,col为列
    Matrix=(type **) malloc(row*sizeof(type *)) ;
    for(int i=0; i<row; i++)
        Matrix[i] = (type *)malloc(col * sizeof(type ));

类似数组a[2][3]，他一共两行，每一行有3个元素，所以为他先分配两行内存，然后每一行再分配3列内存

Matrix类型是type**，先为它分配row行内存，内存类型与Matrix一样
Matrix=(type**) malloc(rowsizeof(type))
每一行分配col列内存，内存类型与Matix[i]一样，也就是type*
Matrix[i] = (type*)malloc(col * sizeof(type ));

其中一个功能的结果：

下面是完整代码

#include <iostream>
#include <malloc.h>
#include <stdio.h>
using namespace std;

typedef struct
{
    //结构体
    int row,col;
    //二维指针，目的是动态分配内存
    float **matrix;
} Matrix;

typedef struct
{
    char *name;
    char *number;
} Student;

Matrix CreateMatrix()
{
    Matrix m;
    int row,col;
    cout << \"输入行数与列数：\" << endl;
    cin >> row >> col;
    float **enterMatrix ;
    enterMatrix=(float**) malloc(row*sizeof(float*)) ;
    for(int i=0; i<row; i++)
        enterMatrix[i] = (float *)malloc(col * sizeof(float));
    cout<<\"输入你的矩阵：\"<<endl;
    for(int i=0; i<row; i++)
    {
        for(int j=0; j<col; j++)
        {
            cin >> enterMatrix[i][j];
        }
    }
    m.col = col;
    m.row = row;
    m.matrix = enterMatrix;
    return m;
}

//初始化一个行为row列为col矩阵
Matrix InitMatrix(int row,int col)
{
    Matrix m;
    float **matrix ;
    matrix=(float**) malloc(row*sizeof(float*)) ;
    for(int i=0; i<row; i++)
        matrix[i] = (float *)malloc(col * sizeof(float));
    for(int i=0; i<row; i++)
    {
        for(int j=0; j<col; j++)
        {
            matrix[i][j] = 0;
        }
    }
    m.col = col;
    m.row = row;
    m.matrix = matrix;
    return m;
}

Matrix add(Matrix m1, Matrix m2)
{
    for(int i=0; i<m1.row; i++)
    {
        for(int j=0; j<m1.col; j++)
        {
            m1.matrix[i][j] = m1.matrix[i][j] +m2.matrix[i][j];
        }
    }
    return m1;
}

Matrix sub(Matrix m1, Matrix m2)
{
    for(int i=0; i<m1.row; i++)
    {
        for(int j=0; j<m1.col; j++)
        {
            m1.matrix[i][j] = m1.matrix[i][j] -m2.matrix[i][j];
        }
    }
    return m1;
}

int calRowCol(Matrix M1,Matrix M2,int row,int col)//row为M1的行 col为m2的列
{
    int result = 0;
    int same = M1.col;
    for(int j=0; j<same; j++)
    {
        result+=M1.matrix[row][j]*M2.matrix[j][col];
    }

    return result;
}


Matrix Mul(Matrix m1, Matrix m2)
{
    Matrix result = InitMatrix(m1.row,m2.col);
    for(int i=0; i<m1.row; i++)
    {
        for(int j=0; j<m2.col; j++)
        {
            result.matrix[i][j] = calRowCol(m1,m2,i,j);
        }
    }
    return result;
}

Matrix numMul(Matrix m, int num)
{
    cout<<\"数值:\"<<num<<endl;
    for(int i=0; i<m.row; i++)
    {
        for(int j=0; j<m.col; j++)
        {
            m.matrix[i][j] = m.matrix[i][j]*num;
        }
    }
    return m;
}

Matrix printMatrix(Matrix m)
{
    for(int i=0; i<m.row; i++)
    {
        for(int j=0; j<m.col; j++)
        {
            cout << m.matrix[i][j] << \"  \";
        }
        cout<<endl;
    }
}

int main()
{
    int num = 0;
    do
    {
        cout<<\"*************************************\\n\";
        cout<<\"*              菜单                 *\\n\";
        cout<<\"*          1.矩阵相加               *\\n\";
        cout<<\"*          2.矩阵相减               *\\n\";
        cout<<\"*          3.矩阵相乘               *\\n\";
        cout<<\"*          4.矩阵数乘               *\\n\";
        cout<<\"*          5.退出                   *\\n\";
        cout<<\"*************************************\\n\";
        cin>>num;
        if(1 == num|| 2 == num || 3 == num)
        {
            cout<<\"请输入矩阵1\"<<endl;
            Matrix m1 = CreateMatrix();
            cout<<\"请输入矩阵2\"<<endl;
            Matrix m2 = CreateMatrix();
            cout<<\"两矩阵为\"<<endl;
            printMatrix(m1);
            cout<<endl;
            printMatrix(m2);
            switch(num)
            {
            case 1:
            {
                if(m1.col!=m2.col || m1.row!=m2.row)
                {
                    cout<<\"行列不同\"<<endl;
                }
                else{
                    cout<<\"结果为：\"<<endl;
                    printMatrix(add(m1,m2));
                }
                break;
            }
            case 2:
            {

                if(m1.col!=m2.col || m1.row!=m2.row)
                {
                    cout<<\"参数错误\"<<endl;
                }
                else{
                    cout<<\"结果为：\"<<endl;
                    printMatrix(sub(m1,m2));
                }
                break;

            }
            case 3:
            {
                if(m1.col!=m2.row)
                {
                    cout<<\"参数错误\"<<endl;
                }
                else{
                    cout<<\"结果为：\"<<endl;
                    printMatrix(Mul(m1,m2));
                }
                break;
            }
            default:
                break;
            }
        }
        else if(4 == num)
        {
            int number = 1;
            cout<<\"请输入矩阵\"<<endl;
            Matrix m = CreateMatrix();
            cout<<\"请输入数值\"<<endl;
            cin>>number;
            cout<<\"矩阵为：\"<<endl;
            printMatrix(m);
            cout<<\"数值为：\"<<endl;
            cout<<number<<endl;
            printMatrix(numMul(m,number));
        }
        cout<<\"按回车继续....\";

        getchar();
        getchar();
        system(\"cls\");
    }
    while(1 == num|| 2 == num || 3 == num ||4 == num);
    return 0;
}