C-阵列未填充时fgets挂起
我使用C-阵列未填充时fgets挂起,c,fgets,C,Fgets,我使用fgets()从stdin获取输入,似乎在缓冲区溢出方面遇到了一些问题。我已经添加了一个while循环,它意味着吃掉所有字符,但是我的代码运行了多次,应该只运行一次 void play_game(void) { int ch; /* Waste */ /* Max input from fgets */ char c[8]; enum cell_contents board[BOARD_HEIGHT][BOARD_WIDTH]; init_boa
fgets()
从stdin
获取输入,似乎在缓冲区溢出方面遇到了一些问题。我已经添加了一个while循环,它意味着吃掉所有字符,但是我的代码运行了多次,应该只运行一次
void play_game(void) {
int ch; /* Waste */
/* Max input from fgets */
char c[8];
enum cell_contents board[BOARD_HEIGHT][BOARD_WIDTH];
init_board(board);
while(!is_game_over(board)) {
display_board(board);
printf("Please enter a move [enter Q or ctrl-D to quit]: ");
if(fgets(c, sizeof(c), stdin)) {
printf("Entered: %s\n", c);
struct move calculated_move = calculate_move(c);
if(is_valid_move(calculated_move, board))
player_move(calculated_move, board);
else
printf("That is an invalid move!\n");
}
/* eat excess data */
if (strlen(c) == sizeof(c)-1)
while((ch = fgetc(stdin)) != '\n' && ch != EOF);
/* eat overfilled data */
//read_rest_of_line();
}
printf("Game over!\n");
game_over(board);
}
以下是我的结果:
Please enter a move [enter Q or ctrl-D to quit]: E4, C4 gfgfd oigjdfogkf dohdfkho dk
Entered: E4, C4
+---+---+---+
1 | o | o | o |
+---+---+---+
2 | o | o | o |
+---+---+---+---+---+---+---+
3 | o | o | o | o | o | o | o |
+---+---+---+---+---+---+---+
4 | o | . | o | . | . | o | o |
+---+---+---+---+---+---+---+
5 | o | o | o | o | o | o | o |
+---+---+---+---+---++---+---+
6 | o | o | o |
+---+---+---+
7 | o | o | o |
+---+---+---+
A B C D E F G
Please enter a move [enter Q or ctrl-D to quit]: Entered: gfgfd o
That is an invalid move!
+---+---+---+
1 | o | o | o |
+---+---+---+
2 | o | o | o |
+---+---+---+---+---+---+---+
3 | o | o | o | o | o | o | o |
+---+---+---+---+---+---+---+
4 | o | . | o | . | . | o | o |
+---+---+---+---+---+---+---+
5 | o | o | o | o | o | o | o |
+---+---+---+---+---++---+---+
6 | o | o | o |
+---+---+---+
7 | o | o | o |
+---+---+---+
A B C D E F G
Please enter a move [enter Q or ctrl-D to quit]: Entered: igjdfog
That is an invalid move!
+---+---+---+
1 | o | o | o |
+---+---+---+
2 | o | o | o |
+---+---+---+---+---+---+---+
3 | o | o | o | o | o | o | o |
+---+---+---+---+---+---+---+
4 | o | . | o | . | . | o | o |
+---+---+---+---+---+---+---+
5 | o | o | o | o | o | o | o |
+---+---+---+---+---++---+---+
6 | o | o | o |
+---+---+---+
7 | o | o | o |
+---+---+---+
A B C D E F G
Please enter a move [enter Q or ctrl-D to quit]:
通过检查数组中的最后一个字符是否为新行修复了此问题
/* eat excess data */
if (strlen(c) == sizeof(c)-1 || c[sizeof(c)-1] != '\n')
read_rest_of_line();
void read_rest_of_line(void){
int ch;
/* remove all characters from the buffer */
while (ch = getc(stdin), ch != '\n' && ch != EOF);
/* clear the error status of the input pointer */
clearerr(stdin);
}
如果您给缓冲区指定了正确的大小,则不会写入超过缓冲区结尾的内容。但是,如果换行符符合缓冲区的要求,它可以添加换行符。至于您的问题,请尝试在调试器中逐行检查代码,同时注意变量及其内容。它可能会帮助您找出问题所在。此外,请小心使用该循环以耗尽剩余的字符。如果用户输入了6个字符和换行符怎么办?然后
strlen(c)==sizeof(c)-1
也将为真,您将开始从下一行读取字符(或者更确切地说,当fgetc
等待输入时,游戏似乎会锁定)。更好的检查是缓冲区中的最后一个字符是否为换行符。如果从stdin
中删除使用剩余字符的循环,会发生什么情况?我将如何处理此Joachim?