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C、双向链表问题

发布于 2024-11-04 00:47:31 字数 5568 浏览 0 评论 0原文

我正在尝试读取用户关于客户的输入。

输入： mike,404 禁止 st,raleigh,nc,27607,123.78

然后将该客户添加到按字母顺序排序的双向链表中。用户可以选择插入条目、删除条目或查看列表。添加用户控件后...我的 sscanf 不再正常工作。我不明白为什么。我不明白为什么我无法在用户控制版本中打印客户值。

另外，有关更新节点前一个字段的语法的任何建议/链接都会非常有帮助：P

提前谢谢您

工作（无需用户控制）：

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define MAXNAMELEN 19
#define MAXADDRLEN 49
#define MAXCITYLEN 19
#define MAXSTATELEN 2

struct aNode {
    char name[MAXNAMELEN];
    char address[MAXADDRLEN];
    char city[MAXCITYLEN];
    char state[MAXSTATELEN];
    int zip;
    float balance;
    struct aNode *next;
    struct aNode *prev; 
};

typedef struct aNode node;
struct aNode *dLList;

void read();
void input();
void print();
void delete();
int insertSort(node*);

int main() {

    //from text file
    read();

    input();  
        /*
    int choice;
    while(1) {
        printf("\n1.INSERT\n2.DELETE\n3.DISPLAY\n4.END\n");
        printf("Enter choice:");
        scanf("%d",&choice);
        switch(choice) {
        case 1:
            input();
            break;
        case 2:
            delete();
            break;
        case 3:
            print();
            break;
        case 4:
            exit(0);
        }
    }
    */
    return(0);
}

//TODO
void read() {

}

void input() {

    struct aNode *current;
    current = (struct aNode *)malloc(sizeof(struct aNode));

    int buff = 120;
    char temp[buff];

    printf("Enter data: ");
    fgets(temp, buff, stdin);
    sscanf(temp, "%[^,]%*c %[^,]%*c %[^,]%*c %[^,]%*c %d%*c %f", 
           current->name, current->address, current->city, current->state,   
           &current->zip, &current->balance);                   

    insertSort(current);

    //only for testing
    printf("%s, %s, %s, %s, %5d, $%9.2f\n", 
            current->name, current->address, current->city, 
            current->state, current->zip, current->balance);
}

void print() {

    struct aNode *p;

    for(p = dLList; p != NULL; p = p->next) {
        printf("%s, %s, %s, %s, %5d, $%9.2f\n", 
               p->name, p->address, p->city, 
               p->state, p->zip, p->balance);
    }
}

//TODO
void delete() {

}

int insertSort(node * current) {

     struct aNode *p;
    struct aNode *q;

    p = (struct aNode *)malloc(sizeof(struct aNode));
    p = current;

    //need to link to previous node   
    if(dLList == NULL || strcmp(dLList->name, p->name) > 0) {
        p->next = dLList;
        p->prev = NULL;
        return(0);
    }else {
        q = dLList;
        while(q->next != NULL && strcmp(q->next->name, q->name) < 0) {
            q = q->next;
        }   
        p->next = q->next;
        q->next = p;
        return(0);
    }   
}

输出：mike，404禁止st，raleigh，nc，27607，$ 123.78

不工作（带用户控制）：

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define MAXNAMELEN 19
#define MAXADDRLEN 49
#define MAXCITYLEN 19
#define MAXSTATELEN 2

struct aNode {
    char name[MAXNAMELEN];
    char address[MAXADDRLEN];
    char city[MAXCITYLEN];
    char state[MAXSTATELEN];
    int zip;
    float balance;
    struct aNode *next;
    struct aNode *prev; 
};

typedef struct aNode node;
struct aNode *dLList;

void read();
void input();
void print();
void delete();
int insertSort(node*);

int main() {

    //from text file
    read();

    //input();

    int choice;
    while(1) {
        printf("\n1.INSERT\n2.DELETE\n3.DISPLAY\n4.END\n");
        printf("Enter choice:");
        scanf("%d",&choice);
        switch(choice) {
        case 1:
            input();
            break;
        case 2:
            delete();
            break;
        case 3:
            print();
            break;
        case 4:
            exit(0);
        }
    }

    return(0);
}

//TODO
void read() {

}

void input() {

    struct aNode *current;
    current = (struct aNode *)malloc(sizeof(struct aNode));

    int buff = 120;
    char temp[buff];

    printf("Enter data: ");
    fgets(temp, buff, stdin);
    sscanf(temp, "%[^,]%*c %[^,]%*c %[^,]%*c %[^,]%*c %d%*c %f", 
           current->name, current->address, current->city, current->state,   
           &current->zip, &current->balance);                   

    insertSort(current);

    //only for testing
    printf("%s, %s, %s, %s, %5d, $%9.2f\n", 
               current->name, current->address, current->city, 
               current->state, current->zip, current->balance);
}

void print() {

    struct aNode *p;

    for(p = dLList; p != NULL; p = p->next) {
        printf("%s, %s, %s, %s, %5d, $%9.2f\n", 
              p->name, p->address, p->city, 
              p->state, p->zip, p->balance);
    }
}

//TODO
void delete() {

}

int insertSort(node * current) {

     struct aNode *p;
    struct aNode *q;

    p = (struct aNode *)malloc(sizeof(struct aNode));
    p = current;

    //need to link to previous node   
    if(dLList == NULL || strcmp(dLList->name, p->name) > 0) {
        p->next = dLList;
        p->prev = NULL;
        return(0);
    }else {
        q = dLList;
        while(q->next != NULL && strcmp(q->next->name, q->name) < 0) {
            q = q->next;
        }   
        p->next = q->next;
        q->next = p;
        return(0);
    }   
}

输出： , , , , 0, $ 0.00

原文

I'm trying to read input from the user about a customer.

Input: mike,404 forbidden st,raleigh,nc,27607,123.78

Then add that customer to a alphabetically sorted, doubly linked list. The user can choose to insert an entry, delete and entry, or view the list. After adding the user control...my sscanf doesn't work properly anymore. I can not figure out why. I don't understand why I'm not able to print customer values in the user control version.

Also, any advice/links about the syntax of updating a nodes previous field would be very helpful :P

Thank you in advance

Working (without user control):

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define MAXNAMELEN 19
#define MAXADDRLEN 49
#define MAXCITYLEN 19
#define MAXSTATELEN 2

struct aNode {
    char name[MAXNAMELEN];
    char address[MAXADDRLEN];
    char city[MAXCITYLEN];
    char state[MAXSTATELEN];
    int zip;
    float balance;
    struct aNode *next;
    struct aNode *prev; 
};

typedef struct aNode node;
struct aNode *dLList;

void read();
void input();
void print();
void delete();
int insertSort(node*);

int main() {

    //from text file
    read();

    input();  
        /*
    int choice;
    while(1) {
        printf("\n1.INSERT\n2.DELETE\n3.DISPLAY\n4.END\n");
        printf("Enter choice:");
        scanf("%d",&choice);
        switch(choice) {
        case 1:
            input();
            break;
        case 2:
            delete();
            break;
        case 3:
            print();
            break;
        case 4:
            exit(0);
        }
    }
    */
    return(0);
}

//TODO
void read() {

}

void input() {

    struct aNode *current;
    current = (struct aNode *)malloc(sizeof(struct aNode));

    int buff = 120;
    char temp[buff];

    printf("Enter data: ");
    fgets(temp, buff, stdin);
    sscanf(temp, "%[^,]%*c %[^,]%*c %[^,]%*c %[^,]%*c %d%*c %f", 
           current->name, current->address, current->city, current->state,   
           ¤t->zip, ¤t->balance);                   

    insertSort(current);

    //only for testing
    printf("%s, %s, %s, %s, %5d, $%9.2f\n", 
            current->name, current->address, current->city, 
            current->state, current->zip, current->balance);
}

void print() {

    struct aNode *p;

    for(p = dLList; p != NULL; p = p->next) {
        printf("%s, %s, %s, %s, %5d, $%9.2f\n", 
               p->name, p->address, p->city, 
               p->state, p->zip, p->balance);
    }
}

//TODO
void delete() {

}

int insertSort(node * current) {

     struct aNode *p;
    struct aNode *q;

    p = (struct aNode *)malloc(sizeof(struct aNode));
    p = current;

    //need to link to previous node   
    if(dLList == NULL || strcmp(dLList->name, p->name) > 0) {
        p->next = dLList;
        p->prev = NULL;
        return(0);
    }else {
        q = dLList;
        while(q->next != NULL && strcmp(q->next->name, q->name) < 0) {
            q = q->next;
        }   
        p->next = q->next;
        q->next = p;
        return(0);
    }   
}

Output: mike, 404 forbidden st, raleigh, nc, 27607, $ 123.78

Not Working (with user control):

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define MAXNAMELEN 19
#define MAXADDRLEN 49
#define MAXCITYLEN 19
#define MAXSTATELEN 2

struct aNode {
    char name[MAXNAMELEN];
    char address[MAXADDRLEN];
    char city[MAXCITYLEN];
    char state[MAXSTATELEN];
    int zip;
    float balance;
    struct aNode *next;
    struct aNode *prev; 
};

typedef struct aNode node;
struct aNode *dLList;

void read();
void input();
void print();
void delete();
int insertSort(node*);

int main() {

    //from text file
    read();

    //input();

    int choice;
    while(1) {
        printf("\n1.INSERT\n2.DELETE\n3.DISPLAY\n4.END\n");
        printf("Enter choice:");
        scanf("%d",&choice);
        switch(choice) {
        case 1:
            input();
            break;
        case 2:
            delete();
            break;
        case 3:
            print();
            break;
        case 4:
            exit(0);
        }
    }

    return(0);
}

//TODO
void read() {

}

void input() {

    struct aNode *current;
    current = (struct aNode *)malloc(sizeof(struct aNode));

    int buff = 120;
    char temp[buff];

    printf("Enter data: ");
    fgets(temp, buff, stdin);
    sscanf(temp, "%[^,]%*c %[^,]%*c %[^,]%*c %[^,]%*c %d%*c %f", 
           current->name, current->address, current->city, current->state,   
           ¤t->zip, ¤t->balance);                   

    insertSort(current);

    //only for testing
    printf("%s, %s, %s, %s, %5d, $%9.2f\n", 
               current->name, current->address, current->city, 
               current->state, current->zip, current->balance);
}

void print() {

    struct aNode *p;

    for(p = dLList; p != NULL; p = p->next) {
        printf("%s, %s, %s, %s, %5d, $%9.2f\n", 
              p->name, p->address, p->city, 
              p->state, p->zip, p->balance);
    }
}

//TODO
void delete() {

}

int insertSort(node * current) {

     struct aNode *p;
    struct aNode *q;

    p = (struct aNode *)malloc(sizeof(struct aNode));
    p = current;

    //need to link to previous node   
    if(dLList == NULL || strcmp(dLList->name, p->name) > 0) {
        p->next = dLList;
        p->prev = NULL;
        return(0);
    }else {
        q = dLList;
        while(q->next != NULL && strcmp(q->next->name, q->name) < 0) {
            q = q->next;
        }   
        p->next = q->next;
        q->next = p;
        return(0);
    }   
}

Output: , , , , 0, $ 0.00

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评论（2）

月下凄凉 2024-11-11 00:47:31

问题是 scanf 不消耗选择字符串末尾的换行符。然后由 input() 中的 fgets 调用读取它，因此输入字符串为空（除了 \n 字符）。

这对我有用：

fgets(temp, buff, stdin);
sscanf(temp, "%d",&choice);

The problem is that scanf doesn't consume the newline at the end of the choice string. It is then read by the fgets call in input(), so the input string is empty (apart from the \n character).

This worked for me:

fgets(temp, buff, stdin);
sscanf(temp, "%d",&choice);
回复 原文
七颜 2024-11-11 00:47:31

dLList 是否在任何地方被初始化为 NULL？
即使是，当您将新节点插入空列表时，它似乎也不会设置为第一个节点。

Is dLList being initialized to NULL anywhere?
And if even if it is, is does not appear to get set to the first node when you insert a new node into an empty list.

回复 原文
~没有更多了~

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