写一个矩阵类CMatrix,基本要求如下：1.实现构造、拷贝构造与析构函数；2.支持任意大小的矩阵，行数和列数可以动态设置（不用修改代码）；3.重载操作符*，实现矩阵相乘；4.重载操作符=，实现矩阵赋值；5.重载操作符++和--，分别实现矩阵元素同时+1和-1；在main函数中对以上功能进行调用。用C语言

好的，下面是一个用C语言实现的简单版本：

#include <stdio.h>
#include <stdlib.h>

typedef struct {
    int rows;
    int cols;
    int **data;
} CMatrix;

CMatrix *createMatrix(int m, int n) {
    CMatrix *mat = (CMatrix *)malloc(sizeof(CMatrix));
    mat->rows = m;
    mat->cols = n;
    mat->data = (int **)malloc(sizeof(int *) * m);
    for (int i = 0; i < m; i++) {
        mat->data[i] = (int *)malloc(sizeof(int) * n);
        for (int j = 0; j < n; j++) {
            mat->data[i][j] = 0;
        }
    }
    return mat;
}

void freeMatrix(CMatrix *mat) {
    for (int i = 0; i < mat->rows; i++) {
        free(mat->data[i]);
    }
    free(mat->data);
    free(mat);
}

CMatrix *copyMatrix(CMatrix *mat) {
    CMatrix *newMat = createMatrix(mat->rows, mat->cols);
    for (int i = 0; i < mat->rows; i++) {
        for (int j = 0; j < mat->cols; j++) {
            newMat->data[i][j] = mat->data[i][j];
        }
    }
    return newMat;
}

CMatrix *multiplyMatrix(CMatrix *mat1, CMatrix *mat2) {
    if (mat1->cols != mat2->rows) {
        printf("Error: The number of columns in the first matrix must be equal to the number of rows in the second matrix.\n");
        return NULL;
    }
    CMatrix *result = createMatrix(mat1->rows, mat2->cols);
    for (int i = 0; i < mat1->rows; i++) {
        for (int j = 0; j < mat2->cols; j++) {
            for (int k = 0; k < mat1->cols; k++) {
                result->data[i][j] += mat1->data[i][k] * mat2->data[k][j];
            }
        }
    }
    return result;
}

void assignMatrix(CMatrix *mat1, CMatrix *mat2) {
    if (mat1 == mat2) {
        return;
    }
    if (mat1->rows != mat2->rows || mat1->cols != mat2->cols) {
        printf("Error: The two matrices must have the same size.\n");
        return;
    }
    for (int i = 0; i < mat1->rows; i++) {
        for (int j = 0; j < mat1->cols; j++) {
            mat1->data[i][j] = mat2->data[i][j];
        }
    }
}

CMatrix *incrementMatrix(CMatrix *mat) {
    for (int i = 0; i < mat->rows; i++) {
        for (int j = 0; j < mat->cols; j++) {
            mat->data[i][j]++;
        }
    }
    return mat;
}

CMatrix *decrementMatrix(CMatrix *mat) {
    for (int i = 0; i < mat->rows; i++) {
        for (int j = 0; j < mat->cols; j++) {
            mat->data[i][j]--;
        }
    }
    return mat;
}

void printMatrix(CMatrix *mat) {
    for (int i = 0; i < mat->rows; i++) {
        for (int j = 0; j < mat->cols; j++) {
            printf("%d ", mat->data[i][j]);
        }
        printf("\n");
    }
}

int main() {
    CMatrix *mat1 = createMatrix(2, 3);
    CMatrix *mat2 = createMatrix(3, 2);
    for (int i = 0; i < 2; i++) {
        for (int j = 0; j < 3; j++) {
            mat1->data[i][j] = i + j;
        }
    }
    for (int i = 0; i < 3; i++) {
        for (int j = 0; j < 2; j++) {
            mat2->data[i][j] = i * j;
        }
    }
    printf("mat1:\n");
    printMatrix(mat1);
    printf("mat2:\n");
    printMatrix(mat2);
    CMatrix *mat3 = multiplyMatrix(mat1, mat2);
    if (mat3 != NULL) {
        printf("mat3:\n");
        printMatrix(mat3);
    }
    incrementMatrix(mat1);
    printf("mat1++:\n");
    printMatrix(mat1);
    CMatrix *mat4 = decrementMatrix(copyMatrix(mat2));
    printf("mat2--:\n");
    printMatrix(mat2);
    printf("mat4:\n");
    printMatrix(mat4);
    freeMatrix(mat1);
    freeMatrix(mat2);
    freeMatrix(mat3);
    freeMatrix(mat4);
    return 0;
}

上述代码定义了一个矩阵结构体`CMatrix`，其成员包括行数、列数和数据矩阵。该结构体提供了一些函数，如创建矩阵、释放矩阵内存、复制矩阵、矩阵相乘、矩阵赋值、矩阵元素+1和矩阵元素-1等。在main函数中进行了上述功能的调用。