Question

我正在编写执行以下操作的程序。我已经完成了我的代码，我觉得很好但是我尝试做以下事情，我无法弄清楚。

1.将指向矩阵的指针传递给函数，并使函数改变矩阵。 main函数应该定义数组，初始化它，然后调用（a）函数来操作它。

2.使用字母＆＃39; A＆＃39;通过＆＃39; Z＆＃39;然后是字母＆＃39; a＆＃39;通过＆＃39; z＆＃39;。这意味着随机游走将达到52个位置。对于这个，我已经有了字母A到Z，但不知道如何使用＆＃39; a＆＃39;到＆＃39; z＆＃39;

Write a program that generates a “random walk” across a 10 x 10 array. The array will contain character (all ‘.’ Initially). The program must randomly “walk” from element to element, always going up, down, left, or right by one element. Z, in the order visited. Here’s an example of the desired output:
A . . . . . . . . .
B C D . . . . . . .
. F E . . . . . . .
H G . . . . . . . .
I . . . . . . . . .
J . . . . . . . . .
K . . R S T U V Y .
L M P Q . . . W X .
. N O . . . . . . .
. . . . . . . . . .

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


int main ()
{


    void printarray(char array[12][12], int x, int y); /*Function prototype*/



        int i = 0, roll = 0, row = 0, col = 0, rowcheck = 0, colcheck = 0; /*i = number of moves. roll = value generated by the random number generator. r = row location. col = column location. rowcheck and colcheck are the incremented and decremented values of row and col respectively, used to check whether a legal move can be performed*/
        char position[12][12], chtr = 'A'; /*position[12][12] = Grid for the walking. chtr = the letters of the Alphabet.*/

        for (row = 0; row < 12; row++) /*Fills the 12 x 12 array with the "." character*/
        {
            for (col = 0; col < 12; col++)
            {
                position[row][col] = '.';
            }
        }

        srand(5000); /*Seeds the random number function*/

        for (i = 0, row = 0, col = 0, rowcheck = 0, colcheck = 0; i < 25;)
        {
            rowcheck = row;
            colcheck = col;
            roll = rand() % 4;
            switch (roll) /*Determines what direction to move starting from the top left corner of the grid (bird's eye view)*/
            {
                case 0: /*Move up*/
                {
                    rowcheck--;
                }
                case 1: /*Move left*/
                {
                    colcheck--;
                }
                case 2: /*Move down*/
                {
                    rowcheck++;
                }
                case 3: /*Move right*/
                {
                    colcheck++;
                }
            }
            if ((rowcheck < 0 || rowcheck > 9) || (colcheck < 0 || colcheck > 9) || (position[rowcheck][colcheck] != '.'))
            {
                continue;
            }
            else
            {
                row = rowcheck;
                col = colcheck;
                position[row][col] = chtr;
                chtr++;
                printarray(position, row, col);
                i++;
            }
        }

        exit (0);
    }

    /*Function declaration*/
    void printarray(char array[12][12], int x, int y){

        printf("CURRENT POSITION %d %d\n", x, y);
        for (x = 0; x < 12; x++) /*Prints out the values of the array*/
        {
            for (y = 0; y < 12; y++)
            {
                printf("%c", array[x][y]);
            }
            printf("\n");
        }
        printf("\n");





    }

Answer 1

好的，你的问题是纯粹的逻辑问题。您遇到的主要问题是：

if ((rowcheck < 0 || rowcheck > 9) || 
    (colcheck < 0 || colcheck > 9) || 
    (position[rowcheck][colcheck] != '.'))

这将在rowcheck或colcheck小于0或大于11的任何时候调用未定义的行为。（无论值是多少都可以设置position[rowcheck][colcheck]，这可以很容易地设置在position的限制之外

您的问题的其余部分是类似的失败，无法在rowcheck语句本身内控制colcheck或switch的值。您需要在递增或递减值之前测试这些值 - 强制值保持在限制范围内，例如：

    switch (roll) {
    case 0:                /*Move up */
        if (rowcheck > 0)
            rowcheck--;
        break;
    ...

我不完全确定你要完成的是什么，但以下将是你的代码的清理，似乎是你正在寻找的（虽然我不确定它是迭代还是增量在您的完整预期范围内）您的代码编写时也不需要math.h，并且string.h包括memset，以消除您的'.'初始化循环。

如果您使用srand (5000);之外的其他内容，您还可以获得更好的随机分布。一个简单的选项是包含time.h并使用srand (time (NULL));

最后，请避免代码中的幻数（例如12和9）。如果你需要常量#define或使用enum来设置全局常量（如下所示）：

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

enum { MAXC = 9, DIM = 12 };

void printarray (char array[DIM][DIM], int x, int y);   /*Function prototype */

int main (void) {

    int i = 0, roll = 0, row = 0, col = 0, rowcheck = 0, colcheck = 0;
    char position[DIM][DIM], chtr = 'A';

    /*Fills the DIM x DIM array with the '.' character */
    memset (position, '.', sizeof position);

    srand (time (NULL));       /* Seeds the random number function */

    for (i = 0, row = 0, col = 0, rowcheck = 0, colcheck = 0; i < 25; i++) {
        rowcheck = row;
        colcheck = col;
        roll = rand () % 4;

        switch (roll) {
        case 0:                /*Move up */
            if (rowcheck > 0)
                rowcheck--;
            break;
        case 1:                /*Move left */
            if (colcheck > 0)
                colcheck--;
            break;
        case 2:                /*Move down */
            if (rowcheck < DIM - 2)
                rowcheck++;
            break;
        case 3:                /*Move right */
            if (colcheck < DIM - 2)
                colcheck++;
            break;
        }

        if (rowcheck > MAXC || colcheck > MAXC || 
            position[rowcheck][colcheck] != '.')
            continue;

        row = rowcheck;
        col = colcheck;
        position[row][col] = chtr;

        if (chtr < 'Y')     /* allow lower and upper case */
            chtr++;
        else if (chtr == 'Z')
            chtr = 'a';
        else if (chtr > 'a' && chtr < 'z')
            chtr++;
        else
            chtr = 'A';

        printarray (position, row, col);
    }

    exit (0);
}

/*Function declaration */
void printarray (char array[DIM][DIM], int x, int y)
{
    printf ("CURRENT POSITION %d %d\n", x, y);
    for (x = 0; x < DIM; x++) { /*Prints out the values of the array */
        for (y = 0; y < DIM; y++) {
            printf ("%c", array[x][y]);
        }
        printf ("\n");
    }
    printf ("\n");
}

仔细检查并告诉我您是否还有其他问题，或者您是否想要将其他信息添加到您打算做的事情中。

如何在函数中传递指针？

1 个答案: