二维数组的初始化及访问
C++可以模拟多维数组,但存储数组的内存是一维的。
编译器将多维数组映射到内存,而内存只沿一个方向延伸。
在C++定义二维数组并使用函数初始化
#include <iostream>
using namespace std;
const int ARRAY_LENGTH = 5;
void init_array(int (*p)[ARRAY_LENGTH], const int size) {
for (int i = 0; i < size; i++) {
for (int j = 0; j < size; j++) {
p[i][j] = i + j + 1;
}
}
}
void print_array(int (*p)[ARRAY_LENGTH], const int size) {
for (int i = 0; i < size; i++) {
for (int j = 0; j < size; j++) {
cout << p[i][j] << " ";
}
cout << endl;
}
}
int main()
{
int array[ARRAY_LENGTH][ARRAY_LENGTH] = {0};
int (*p)[5] = array; //定义数组指针并初始化
cout << "init_array" << endl;
init_array(p, ARRAY_LENGTH);
cout << "print_array" << endl;
print_array(p, ARRAY_LENGTH);
//二维数组的访问方式
cout << endl;
cout << "array[2][2]: " << array[2][2] << endl;
cout << "*(array[2] + 2): " << *(array[2] + 2) << endl;
cout << "*(*(array+2) + 2): " << *(*(array+2) + 2) << endl;
cout << "*(array[0] + 2*5 + 2): " << *(array[0] + 2*5 + 2) << endl;
cout << endl;
cout << "p[2][2]: " << p[2][2] << endl;
cout << "*(p[2] + 2): " << *(p[2]+2) << endl;
//int a[5], *p;
//p = a;
//a[i] == p[i] == *(p + i) == *(a + i)
cout << "*(*(p+2) + 2): " << *(*(p+2) + 2) << endl;
cout << "*(p[0] + 2*5 + 2): " << *(p[0] + 2*5 +2) << endl;
cout << endl;
return 0;
}
程序运行结果如下:
init_array
print_array
1 2 3 4 5
2 3 4 5 6
3 4 5 6 7
4 5 6 7 8
5 6 7 8 9
array[2][2]: 5
*(array[2] + 2): 5
*(*(array+2) + 2): 5
*(array[0] + 2*5 + 2): 5
p[2][2]: 5
*(p[2] + 2): 5
*(*(p+2) + 2): 5
*(p[0] + 2*5 + 2): 5