C/C++ 二维数组

使用C语言用到了二维数组

#include <iostream>
#include <stdlib.h>
using namespace std;

void print_arr_fun1(int arr[][3], int row){
    for (int i = 0; i < row; ++i){
        for (int j = 0; j < 3; ++j)
            cout << arr[i][j] << " ";
        cout << endl;
    }   
}

void print_arr_fun2(int *arr, int row, int col){
    for (int i = 0; i < row; ++i){
        for (int j = 0; j < col; ++j)
            cout << *(arr + i * row + j) << " ";    
        cout << endl;
    }   
}

void print_arr_fun3(int **arr, int row, int col){
    for (int i = 0; i < row; ++i){
        for (int j = 0; j < col; ++j)
            cout << arr[i][j] << " ";   
        cout << endl;
    }   
}

int main(){
    const int row = 2;  //这里是const
    const int col = 3;
    int arr1[row][col];
    for (int i = 0; i < row; ++i)
        for (int j = 0; j < col; ++j)
            arr1[i][j] = i * col + j;

    cout << "print_arr_fun1---------------------------" << endl;
    print_arr_fun1(arr1, row);
    cout << "print_arr_fun2---------------------------" << endl;
    print_arr_fun2((int*)arr1, row, col);

    cout << "print_arr_fun3---------------------------" << endl;
    int **arr2 = (int**)malloc(sizeof(int*) * row);
    //malloc
    for (int i = 0; i < row; ++i)
        arr2[i] = (int*)malloc(sizeof(int) * col);
    for (int i = 0; i < row; ++i)
        for (int j = 0; j < col; ++j)
            arr2[i][j] = i * col + j;
    print_arr_fun3(arr2, row, col);

    //free
    for (int i = 0; i < row; ++i)
        free(arr2[i]);
    free(arr2);

    return 0;
}

输出:

print_arr_fun1---------------------------
0 1 2 
3 4 5 
print_arr_fun2---------------------------
0 1 2 
2 3 4 
print_arr_fun3---------------------------
0 1 2 
3 4 5