Question

列表对我来说似乎很难。我想找到文件中的最小元素：1 5 8 6 4 8 6 48 9。它是1，我想删除1。我可以找到最小的元素但不能删除它。我发现最小的元素位置但不是值。我尝试从网络上复制删除功能，但由于我是C的新手，我无法理解它。它写了一个错误，解除了不完整类型的错误。请帮忙。发布整个代码，因为它应该更方便理解。

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

typedef struct linkedList {
    int value;
    struct linkedList *next;
} linkedList, head;

linkedList *readList(linkedList *head) {
    FILE *dataFile;
    dataFile = fopen("duom.txt", "r");
    if (dataFile == NULL) {
        printf("Nepasisekė atidaryti failo\n");
    } else {
        printf("Duomenų failą pavyko atidaryti\n");
    }
    while (!feof (dataFile))
        if (head == NULL) {
            head = malloc(sizeof(linkedList));
            fscanf(dataFile, "%d", &head->value);
            head->next = NULL;
        } else {
            struct linkedList *current = head;
            struct linkedList *temp = malloc(sizeof(linkedList));
            while (current->next != NULL) {
                current = current->next;
            }
            fscanf(dataFile, "%d", &temp->value);
            current->next = temp;
            temp->next = NULL;
        }
    return head;
}

void search(linkedList *head, int *lowest) {
    int a[100];
    int i = 0;
    int minimum;
    int b = 0;
    linkedList *current = head;

    while (current != NULL) {
        a[i] = current->value;
        current = current->next;
        i++;
    }
    b = i;
    i = 0;
    minimum = a[0];
    while (b > 0) {
        if (minimum > a[i]) {
            minimum = a[i];
            lowest = i;
        }
        i++;
        b--;
    }
}

void deleteNode(struct node **head_ref, int key) {
    struct node* temp = *head_ref, *prev;

    if (temp != NULL && temp->data == key) {
        *head_ref = temp->next;   // Changed head
        free(temp);               // free old head
        return;
    }

    while (temp != NULL && temp->data != key) {
        prev = temp;
        temp = temp->next;
    }

    if (temp == NULL) 
        return;
    prev->next = temp->next;
    free(temp);
}

void printList(linkedList *head) {
    linkedList *current = head;
    while (current != NULL) {
        printf("%d->", current->value);
        current = current->next;
    }
    printf("NULL\n");
    return;
}

int main() {
    linkedList *A = NULL;
    A = readList(A);
    search(A);
    head = head->next;
    minimum = head->value;
    headk->next = head->next;
    free(head);
    printList(A);
    return 0;
}

Answer 1

像这样

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

typedef struct linkedList{
    int value;
    struct linkedList *next;
} linkedList, node;

linkedList *readList(void){
    FILE *dataFile;
    dataFile = fopen("duom.txt", "r");
    if(dataFile == NULL) {
        perror("file open");
        return NULL;
    }

    int v;
    node head = {0, NULL}, *curr = &head;
    while (1 == fscanf(dataFile, "%d", &v)){
        node *new_node = malloc(sizeof(node));
        if(new_node == NULL){
            perror("malloc");
            break;
        }
        new_node->value = v;
        new_node->next = NULL;
        curr = curr->next = new_node;
    }
    fclose(dataFile);
    return head.next;
}

int searchMin(linkedList *head){
    if(head == NULL){
        fprintf(stderr, "%s: The list MUST NOT be NULL.\n", __func__);
        return INT_MIN;
    }
    int min = head->value;
    node *p = head->next;
    while(p){
        if(p->value < min)
            min = p->value;
        p = p->next;
    }
    return min;
}

void deleteNode(node **head_ref, int key){
    node *curr = *head_ref, *prev = NULL;

    while (curr != NULL && curr->value != key){
        prev = curr;
        curr = curr->next;
    }

    if (curr == NULL) return;//not found
    if(prev)
        prev->next = curr->next;
    else
        *head_ref = curr->next;
    free(curr);
}

void printList(linkedList *head){
    node *current = head;

    while (current != NULL) {
        printf("%d->", current->value);
        current = current -> next;
    }
    puts("NULL");
}

void freeList(linkedList *list){
    while(list){
        node *temp = list;
        list = list->next;
        free(temp);
    }
}

int main(void){
    linkedList *A = readList();
    int min = searchMin(A);
    printList(A);
    deleteNode(&A, min);
    printList(A);
    freeList(A);

    return 0;
}

Answer 2

请尝试此程序可以帮助您。

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

struct node {
    int data;
    struct node *next;
};

void push(struct node **head_ref, int new_data) {
    struct node *new_node = (struct node *) malloc(sizeof(struct node));
    new_node->data = new_data;
    new_node->next = (*head_ref);
    (*head_ref) = new_node;
}

void deleteNode(struct node **head_ref, int key) {
    struct node *temp = *head_ref, *prev;
    if (temp != NULL && temp->data == key) {
        *head_ref = temp->next;
        free(temp);
        return;
    }
    while (temp != NULL && temp->data != key) {
        prev = temp;
        temp = temp->next;
    }
    if (temp == NULL) return;
    prev->next = temp->next;
    free(temp);
}

void printList(struct node *node) {
    while (node != NULL) {
        printf(" %d ", node->data);
        node = node->next;
    }
}

void min(struct node **q) {
    struct node *r;
    int min = INT_MAX;;
    r = *q;
    while (r != NULL) {
        if (r->data < min) {
            min = r->data;
        }
        r = r->next;
    }
    printf("The min is %d", min);
    deleteNode(q, min);
    printf("\n");
}

int main() {
    struct node *head = NULL;
    FILE *file = fopen("duom.txt", "r");
    int i = 0;
    fscanf(file, "%d", &i);
    while (!feof(file)) {
        push(&head, i);
        fscanf(file, "%d", &i);
    }
    fclose(file);
    puts("Created Linked List: ");
    printList(head);
    min(&head);
    puts("\nLinked List after Deletion of minimum: ");
    printList(head);
    return 0;
}

档案duom.txt

1 5 8 6 4 8 6 48 9

测试

./a.out 
Created Linked List: 
 9  48  6  8  4  6  8  5  1 The min is 1

Linked List after Deletion of minimum: 
 9  48  6  8  4  6  8  5 ⏎

c链表删除最小元素

2 个答案: