使用fprintf正确保存了数据,但打印出了奇怪的值

时间:2019-03-05 15:26:50

标签: c printf scanf fopen

我创建了一个结构:

typedef struct aeroplane
{
  int seat;
  char rsv[10];
  char fName[20];
  char lName[20];
} AERO;

并在主函数中创建一个数组,然后对其进行初始化:

#define ROWS 3
#define COLS 4

AERO arr[ROWS][COLS] =
  {
    {
      {0, "Empty", "NULL", "NULL"},
      {0, "Empty", "NULL", "NULL"},
      {0, "Empty", "NULL", "NULL"},
      {0, "Empty", "NULL", "NULL"}
    },
    {
      {0, "Empty", "NULL", "NULL"},
      {0, "Empty", "NULL", "NULL"},
      {0, "Empty", "NULL", "NULL"},
      {0, "Empty", "NULL", "NULL"}
    },
    {
      {0, "Empty", "NULL", "NULL"},
      {0, "Empty", "NULL", "NULL"},
      {0, "Empty", "NULL", "NULL"},
      {0, "Empty", "NULL", "NULL"}
    }
  };

我使用此函数将数组保存到test.dat

void save(AERO * arr, FILE * fp)
{
  for (int i = 0; i < ROWS; i++)
  {
    for (int j = 0; j < COLS; j++)
    {
      fprintf(fp, "%d %s %s %s\n",
      ((arr + i) + j) -> seat, ((arr + i) + j) -> rsv, ((arr + i) + j) -> fName, ((arr + i) + j) -> lName);
    }
    fprintf(fp, "\n");
  }
}

这是test.dat显示的内容:

0 Empty NULL NULL
0 Empty NULL NULL
0 Empty NULL NULL
0 Empty NULL NULL

0 Empty NULL NULL
0 Empty NULL NULL
0 Empty NULL NULL
0 Empty NULL NULL

0 Empty NULL NULL
0 Empty NULL NULL
0 Empty NULL NULL
0 Empty NULL NULL

看起来像我的意图。

但是,当我使用此函数检索数据时:

void read(AERO * arr, FILE * fp)
{
  for (int i = 0; i < ROWS; i++)
  {
    for (int j = 0; j < COLS; j++)
    {
      fscanf(fp, "%d %s %s %s",
      &((arr + i) + j) -> seat, ((arr + i) + j) -> rsv, ((arr + i) + j) -> fName, ((arr + i) + j) -> lName);
    }
  }
}

然后将其打印出来:

for (int i = 0; i < ROWS; i++)
  {
    for (int j = 0; j < COLS; j++)
    {
      printf("dummy[%d][%d]\nseat = %d\nrsv = %s\nfName = %s\nlName = %s\n\n",
      i, j, dummy[i][j].seat, dummy[i][j].rsv, dummy[i][j].fName, dummy[i][j].lName);
    }
  }

输出不是我想要的:

dummy[0][0]
seat = 0
rsv = Empty
fName = NULL
lName = NULL

dummy[0][1]
seat = 0
rsv = Empty
fName = NULL
lName = NULL

dummy[0][2]
seat = 0
rsv = Empty
fName = NULL
lName = NULL

dummy[0][3]
seat = 0
rsv = Empty
fName = NULL
lName = NULL

dummy[1][0]
seat = 0
rsv = Empty
fName = NULL
lName = NULL

dummy[1][1]
seat = 0
rsv = Empty
fName = NULL
lName = NULL

dummy[1][2]
seat = 0
rsv =
fName =
lName = ▒▒

dummy[1][3]
seat = -2144188312
rsv =
fName =
lName =

dummy[2][0]
seat = 0
rsv =
fName =
lName =

dummy[2][1]
seat = 970037024
rsv = ▒
fName =
lName = ▒

dummy[2][2]
seat = -14080
rsv =
fName =
lName =

dummy[2][3]
seat = 31
rsv =
fName =
lName =

我希望输出已经定义了3行4列。但是它不仅返回较小的值,而且还返回损坏的值。我错过了什么吗?

1 个答案:

答案 0 :(得分:0)

AERO[ROWS][COLS]AERO*不兼容。打开编译器警告,并注意警告。                     – pmg