Question

我是C编程的新手。我正在尝试运行此程序，该程序接受来自用户的人员名称，并将这些名称存储在结构数组中。

输入名称的消息将打印在控制台上，但在用户输入字符串之前，将显示下一个语句。 Prog是 -

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

//10 students taken in per batch
#define NUMBER_OF_SEATS 10
#define ROLL_NUM 4

//5 faculty members teach every batch
#define NUMBER_OF_FACULTY 5
#define LENGTH_OF_NAME 50


int main () 
{
//Details of a department
struct dept 
{
    char faculty[NUMBER_OF_FACULTY][LENGTH_OF_NAME];
    int id_students[ROLL_NUM];
    char students[NUMBER_OF_SEATS][LENGTH_OF_NAME];

};

struct dept batch2010[NUMBER_OF_SEATS];
struct dept *point_batch2010 = batch2010;

//Printing the size of the defined strucutre
printf("%lud",sizeof(struct dept));


for (int i = 0; i<NUMBER_OF_FACULTY; i++) 
{
    printf("\nEnter name of faculty %d teaching batch of 2010\n",i+1);
    gets(*point_batch2010->faculty);
    point_batch2010++;
}
printf("\n\n");
point_batch2010 = batch2010;

printf("\nFaculty members are:\n");
for (int i = 0; i<NUMBER_OF_FACULTY; i++)
{
    puts(*point_batch2010->faculty);
    point_batch2010++;
}
point_batch2010 = batch2010;

**for (int i = 0; i<NUMBER_OF_SEATS; i++) 
{
    printf("\nEnter name of student studying in batch of 2010");
    fgets(*point_batch2010->students, LENGTH_OF_NAME, stdin);
    printf("\nEnter roll number of student %d studying in batch 0f 2010\n",i+1);
    scanf("%d",point_batch2010->id_students);
}**

for (int i = 0; i<NUMBER_OF_SEATS; i++) 
{
    puts(*batch2010[i].students);
}
return 0;
}

控制台上的错误是 -

Enter name of student studying in batch of 2010Anita
Enter roll number of student 1 studying in batch 0f 2010
1234
Enter name of student studying in batch of 2010
Enter roll number of student 2 studying in batch 0f 2010
3467
Enter name of student studying in batch of 2010
Enter roll number of student 2 studying in batch 0f 2010

我猜这个错误与'\ n'字符有关，我可以将代码分解为2个不同的for循环，但问题可以在这个循环中排序吗？

感谢。

Answer 1

Faculty是2d数组。你可以尝试这样的东西来循环询问来自控制台的输入。

gets(point_batch2010->faculty[i]);

Answer 2

scanf有一个坏习惯，就是在输入流上留下用户输入的换行符。尝试在其后添加第二个scanf，消耗单个字符（用户键入的\ n）有关scanf为邪恶的详细解释，请参阅http://c-faq.com/stdio/scanfprobs.html和儿童附：其他一些受访者指出，您的代码中还存在其他问题，但这应该可以帮助您解决这个具体问题。

Answer 3

for (int i = 0; i<NUMBER_OF_SEATS; i++) 
{
    printf("\nEnter name of student studying in batch of 2010");
    fgets(*point_batch2010->students, LENGTH_OF_NAME, stdin);
    printf("\nEnter roll number of student %d studying in batch 0f 2010\n",i+1);
    scanf("%d",point_batch2010->id_students);
}

问题是fgets读入\n而scanf将其留在缓冲区中。

在for读取输入后的scanf循环中，\n位于缓冲区中，然后在下一次迭代中由fgets读取。 scanf读取直到它到达空格或换行符，而fgets读取neline字符

你需要做

while ( getchar() != '\n' );

在scanf行之后。

Answer 4

建议将人类输入与扫描（解析）分开，从而避免邪恶的scanf()。

for (int i = 0; i<NUMBER_OF_SEATS; i++)  {
  char buffer[LENGTH_OF_NAME];
  printf("\nEnter name of student studying in batch of 2010");
  fgets(buffer, sizeof(buffer), stdin);
  sscanf(buffer, "%[^\n]", *point_batch2010->students);
  // using fgets(*point_batch2010->students, ...) puts the '\n' in the name  

  char number[256];
  printf("\nEnter roll number of student %d studying in batch 0f 2010\n",i+1);
  fgets(number, sizeof(number), stdin);
  sscanf(number, "%d",point_batch2010->id_students);
}

注意：我认为您希望自己的结构为int id_students /*[ROLL_NUM] */;和sscanf(number, "%d",/* note the & */ & (point_batch2010->id_students));

程序不接受来自控制台的字符串输入

4 个答案: