Question

当我运行它时，我的第一个fgets会被忽略，直接跳到第二个fgets为什么会这样？我希望fgets能够获得学生姓名的用户输入，但它并没有。所以我无法得到学生的名字

printf("Enter the name of the student\n");
            fgets(name, 100, stdin);
printf("Enter the gender of the student\n");
            fgets(gender,100,stdin);
printf("Enter the course of the student\n");
            fgets(course,100,stdin);
            number++;

我的print_begin（）函数可以输出2个输入数据，这意味着如果studentlist有4个结构，它只打印出2个。但是我的print_last可以很好地打印所有输入。

void print_begin(){

struct node *tempdisplay;
tempdisplay = studentlist;

if (studentlist == NULL)
printf("List is empty\n");
else
{
    while (tempdisplay!= NULL)
    {
    printf("student name   = %s", tempdisplay->student_name);
    printf("student gender = %s", tempdisplay->student_gender);
    printf("student course = %s", tempdisplay->student_course);
    printf("Student Number = %d\n\n", tempdisplay->student_number);
    tempdisplay = tempdisplay->next;
    }
}
printf("\n\nPress any key to go back main menu\n");
getch();
}

这是整个代码

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

struct node
{
    char student_name[40];
    char student_gender[40];
    char student_course[40];
    int student_number;
    struct node *next;
    struct node *prev;
}*newnode, *studentlist,*temp,student;

void insert_last(){

}

void print_begin(){

    struct node *tempdisplay;
    tempdisplay = studentlist;

    if (studentlist == NULL)
        printf("List is empty\n");
    else
    {
        while (tempdisplay!= NULL)
        {
            printf("student name   = %s", tempdisplay->student_name);
            printf("student gender = %s", tempdisplay->student_gender);
            printf("student course = %s", tempdisplay->student_course);
            printf("Student Number = %d\n\n", tempdisplay->student_number);
            tempdisplay = tempdisplay->next;
        }
    }
    printf("\n\nPress any key to go back main menu\n");
    getch();
}

void print_last(){
    struct node *tempdisplay;
    tempdisplay = studentlist;

    if (studentlist == NULL)
        printf("List is empty\n");
    else
    {
        while (tempdisplay->next != NULL)
        {
            tempdisplay = tempdisplay->next;
        }
        while (tempdisplay != NULL)
        {
            printf("student name   = %s", tempdisplay->student_name);
            printf("student gender = %s", tempdisplay->student_gender);
            printf("student course = %s", tempdisplay->student_course);
            printf("Student Number = %d\n\n", tempdisplay->student_number);
            tempdisplay = tempdisplay->prev;
        }
    }
    printf("\n\nPress any key to go back main menu\n");
    getch();
}

void remove_student(){

}

void insert_new(char name[], char xgender[], char xcourse[], int number){
    newnode = NULL;
    newnode = (struct node*)malloc(sizeof (struct node));
    strcpy(newnode->student_name,name);
    strcpy(newnode->student_gender, xgender);
    strcpy(newnode->student_course, xcourse);
    newnode->student_number = number;
    newnode->next = NULL;
    newnode->prev = NULL;

    if (studentlist == NULL)
    {
        studentlist = newnode;
    }
    else
    {
        while (studentlist->next != NULL)
        {
            studentlist = studentlist->next;
        }
        newnode->prev = studentlist;
        studentlist->next = newnode;
    }

    printf("Insert success\n");
    printf("Press any key to go back main menu\n");
    getch();
}

main()
{
    studentlist=NULL;
    char name[40];
    char gender[40];
    char course[40];
    int number = 0;
    int main_choice;

    do{
        printf("\n");
        printf("\n");
        printf("\n");
        printf("               1.Add a new student to the beginning\n");
        printf("               2.Add a new student to the end\n");
        printf("               3.Print out the entire list from the beginning\n");
        printf("               4.Print out the entire list from the end\n");
        printf("               5.Remove a student from the list\n");
        printf("               6.Quit the program\n");
        printf("\n\nEnter the number of the options\n");
        scanf("%d", &main_choice);
        switch (main_choice){
        case 1: {
                    printf("Enter the name of the student\n");
                    fgets(name, 100, stdin);
                    printf("Enter the gender of the student\n");
                    fgets(gender,100,stdin);
                    printf("Enter the course of the student\n");
                    fgets(course,100,stdin);
                    number++;

                    insert_new(name,gender,course,number);
        }break;
        case 2: insert_last(); break;
        case 3: print_begin(); break;
        case 4: print_last(); break;
        case 5: remove_student(); break;
        case 6:{
                   printf("\n\n\nThe program is closing...\n...\n");
                   return 0;
                }break;
        }
        system("cls");
    } while (main_choice != 6);
}

Answer 1

您遇到问题的原因是

与评论中提到的@pmg相同的理由。 fgets读取由于scanf而留下的空行。要解决此问题，请使用fgets读取mainchoice到临时char缓冲区。使用atoi将其转移到int并存储在x中。其余的程序将是相同的。尝试avoid scanf。
在insert_new中，您正在更改studentlist指针。因此，这从开始打印时会导致问题。使用临时变量直到结束。不要改变studentlist。应始终指向列表的开头。以与print函数中相同的方式执行。

Fgets被忽略＆amp;程序只读取2个输入数据（链表）

1 个答案: