如何将双指针用于二维矩阵? [英] How can a double pointer be used for a two dimensional matrix?
问题描述
我正在通过实施Conway的《人生游戏》来尝试C.
I am trying my hand at C by implementing Conway's game of Life.
我试图动态地构建两个网格(int矩阵)，一个用于当前网格，一个用于下一代网格，因此在确定下一代的外观之后，我只是交换指针.
I am trying to dynamically build two grids (int matrices), one for the current and one for the next generation, so after I determine what the next generation looks like, I just swap pointers.
起初，我无可救药地尝试定义指向int * grid之类的网格的指针，您不能使用像[][]这样的第二组括号来下标，因为-很显然，第一组括号返回一个int.
At first I tried hopelessly to define the pointer to the grid like int * grid, which you cannot subscript with a second set of brackets like [][] because - obviously - the first set of brackets returns an int.
我也尝试了类似int * grid[HEIGHT][WIDTH]的方法，但这给将这样一个指针分配给另一个指针带来了问题. (实际上，我不知道它在内存中到底有什么作用！)
I also tried something like int * grid[HEIGHT][WIDTH], but this gives problems assigning one pointer like this to another. (And in fact, I have no idea what this really does in memory!)
出于天真的希望，我认为以下内容在跨过双指针后可能会起作用.该程序可以编译，但是在指定的行上运行时会失败. (在Windows中，除了问题事件名称"为APPCRASH之外，我没有其他详细信息.)
In my naïve hopefulness, I thought the following could work after stumbling across double pointers. The program compiles, but fails when running on the line indicated. (In Windows, I get no more detail other than that the Problem Event Name is APPCRASH).
免责声明:这不是实际程序，仅是问题的概念证明.
DISCLAIMER: This is not the actual program, just a proof of concept for the problem.
#include <stdio.h>
#include <stdlib.h>
int HEIGHT = 20;
int WIDTH = 20;
int ** curr_gen; // Current generation
int ** next_gen; // Next generation
/* Entry Point main */
int main(int argc, char** argv) {
// Allocate memory for the grids
curr_gen = malloc(sizeof (int) * WIDTH * HEIGHT);
next_gen = malloc(sizeof (int) * WIDTH * HEIGHT);
curr_gen[0][0] = 0; //<< PROGRAM FAILS HERE
// Release heap resources
free(curr_gen);
free(next_gen);
return 0;
}
