Question

我真的不知道哪个标题更适合描述我的问题。我通过VirtualBox使用Linux。我正在使用gcc编译器。到目前为止，我一直在编写代码（300行），没有类似的问题。突然间，如果我放置一个新变量并设置一个值，我代码中的其他变量就会改变它们的值。我想知道我是否需要清理记忆或其他东西。

do
{
    rand_arr = rpermute(dim_x * dim_y);
    flag = 0;

    for (t = 0; t < (dim_x * dim_y); t++)
    {
        x = rand_arr[t] / dim_x;
        y = rand_arr[t] % dim_x;

        if (arr[x][y] == 255)
        {
            current_distance = sqrt(pow(exit[0][0] - x, 2) + pow(exit[0][1] - y, 2));

            if (x != 0 && arr[x - 1][y] != 254)
            {
                distance_up = sqrt(pow(exit[0][0] - (x - 1), 2) + pow(exit[0][1] - y, 2));
            }
            else
            {
                distance_up = max_distance + 10000000;
            }

            // Here there is a code computing similar math operations as
            // current_distance and distance_up

            min_dist[0] = distance_up;
            min_dist[1] = distance_back;

            // Here i continue setting in the min_dist array all the variables
            // Here there is a bubblesort code to arrange the min_dist array

            k = 0;
            do
            {
                if (distance_up == min_dist[k] && arr[x - 1][y] == 0 && distance_up < current_distance)
                {
                    arr[x - 1][y] = 255;
                    arr[x][y] = 0;
                    flag = 1;
                    break;
                }
                else if (distance_back == min_dist[k] && arr[x][y - 1] == 0 && distance_back < current_distance)
                {
                    arr[x][y - 1] = 255;
                    arr[x][y] = 0;
                    flag = 1;
                    break;
                }

                // Here there is a code with if statements similar to the two above

                k++;
            } while (k < 4  &&  min_dist[k] < current_distance);
        }
    }
    ...
} while (...)

因此，在此循环之前的每个变量都保持不变，但如果我只设置一个新变量，例如int test=0;，则每个变量在此循环中都会发生变化，尽管新变量是独立的。我也在函数中使用malloc;我想知道这是不是问题，但到目前为止我没有任何问题。

Answer 1

#include <assert.h> /* <<-- Here */

do
{
    rand_arr = rpermute(dim_x * dim_y);
    flag = 0;

    for (t = 0; t < (dim_x * dim_y); t++)
    {
        x = rand_arr[t] / dim_x;
        y = rand_arr[t] % dim_x;

        if (arr[x][y] == 255)
        {
            current_distance = sqrt(pow(exit[0][0] - x, 2) + pow(exit[0][1] - y, 2));

            if (x != 0 && arr[x - 1][y] != 254)
            {
                distance_up = sqrt(pow(exit[0][0] - (x - 1), 2) + pow(exit[0][1] - y, 2));
            }
            else
            {
                distance_up = max_distance + 10000000;
            }

            // Here there is a code computing similar math operations as
            // current_distance and distance_up

            min_dist[0] = distance_up;
            min_dist[1] = distance_back;

            // Here i continue setting in the min_dist array all the variables
            // Here there is a bubblesort code to arrange the min_dist array

            k = 0;
            do
            {
                if (distance_up == min_dist[k] && arr[x - 1][y] == 0 && distance_up < current_distance)
                {
                    assert (x > 0); // <<-- Here
                    arr[x - 1][y] = 255;
                    arr[x][y] = 0;
                    flag = 1;
                    break;
                }
                else if (distance_back == min_dist[k] && arr[x][y - 1] == 0 && distance_back < current_distance)
                {
                    assert (y > 0); // <<--- Here
                    arr[x][y - 1] = 255;
                    arr[x][y] = 0;
                    flag = 1;
                    break;
                }

                // Here there is a code with if statements similar to the two above

                k++;
            } while (k < 4  &&  min_dist[k] < current_distance);
        }
    }
    ...
} while (1); // <<-- Here

设置一个新的自变量会改变c中的所有其他变量

1 个答案: