c - 如何使用 memset 设置填充数组

Question

我有一个包含 GameBoard 的 Player 结构，它是一个二维字符数组。

当我使用 memset 时，它没有设置数组

我试过使用开发板的地址(&、*)但不使用这些符号

如果我在“initializeBoard”中使用指向 Player 变量的指针，但赋值说明不使用指针，我可以让它工作

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

const int ROWS = 10;
const int COLS = 10;

const char *PLAYERONE = "Player 1";
const char *PLAYERTWO = "Player 2";
const char WATER = '~';
const int NUM_SHIPS = 5;

typedef struct gameBoard {
    char board[ROWS][COLS];
} GameBoard;

typedef struct human {
    char name[20];
    GameBoard gameBoard;
} Player;

// function prototypes

void displayGameBoard(Player player);
void initializeBoard(Player player);
void initializePlayer(Player *player, const char *name);






// main function
int main() {
    Player playerOne;
    Player playerTwo;
    // call function welcomeScreen

    initializePlayer(&playerOne, PLAYERONE);
    // end program
    return 0;
}

void displayGameBoard(Player player) {
    int row;
    int col;
    printf("%s's Game Board\n", player.name);
    printf("---------------------------------------------\n");
    printf("|   | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |\n");
    printf("---------------------------------------------\n");
    for (row = 0; row < ROWS; row++) {
        printf("| %d |", row);
        for (col = 0; col < COLS; col++) {
            printf(" %c |", player.gameBoard.board[row][col]);
        }
        printf("\n");
    }
    printf("---------------------------------------------");
}

void initializeBoard(Player player) {
    memset(*player.gameBoard.board, WATER, sizeof(player.gameBoard.board));
}

void initializePlayer(Player *player, const char *name) {
    char playerName[20];
    GameBoard playerBoard;
    strcpy(player->name, playerName);
    player->gameBoard = playerBoard;
    initializeBoard(*player);
    displayGameBoard(*player);
}

我希望结果用'~'填充，但它要么破坏整个终端要么打印空白

Answer 1

这里:

void initializeBoard(Player player) {
    memset(*player.gameBoard.board, WATER, sizeof(player.gameBoard.board));
}

您正在通过复制而不是引用传递 Player 对象。您正在设置的对象不是您打算设置的对象，并且在任何情况下都是临时的。在堆栈上传递大型结构也是低效的(在这种情况下，您可能还需要重新考虑 displayGameBoard() 的签名)。此外，成员 board 不需要取消引用。

void initializeBoard(Player* player);

...

void initializeBoard(Player* player) 
{
    memset( player->gameBoard.board, WATER, sizeof(player->gameBoard.board));
}

然后在initializePlayer()中这样调用:

initializeBoard(player);