写一串单链表通讯录管理系统的C语言代码

下面是一个简单的单链表通讯录管理系统的C语言代码，包含添加联系人、删除联系人、查找联系人、显示所有联系人等功能：

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

typedef struct Contact {
    char name[50];
    char phone[20];
    struct Contact *next;
} Contact;

Contact *head = NULL;

void addContact() {
    Contact *newContact = malloc(sizeof(Contact));
    printf("Enter name: ");
    scanf("%s", newContact->name);
    printf("Enter phone number: ");
    scanf("%s", newContact->phone);
    newContact->next = NULL;
    if (head == NULL) {
        head = newContact;
    } else {
        Contact *p = head;
        while (p->next != NULL) {
            p = p->next;
        }
        p->next = newContact;
    }
    printf("Contact added successfully\n");
}

void deleteContact() {
    char name[50];
    printf("Enter name to delete: ");
    scanf("%s", name);
    if (head == NULL) {
        printf("Contact not found\n");
    } else if (strcmp(head->name, name) == 0) {
        Contact *temp = head;
        head = head->next;
        free(temp);
        printf("Contact deleted successfully\n");
    } else {
        Contact *p = head;
        while (p->next != NULL && strcmp(p->next->name, name) != 0) {
            p = p->next;
        }
        if (p->next == NULL) {
            printf("Contact not found\n");
        } else {
            Contact *temp = p->next;
            p->next = temp->next;
            free(temp);
            printf("Contact deleted successfully\n");
        }
    }
}

void searchContact() {
    char name[50];
    printf("Enter name to search: ");
    scanf("%s", name);
    Contact *p = head;
    while (p != NULL && strcmp(p->name, name) != 0) {
        p = p->next;
    }
    if (p == NULL) {
        printf("Contact not found\n");
    } else {
        printf("Name: %s\nPhone: %s\n", p->name, p->phone);
    }
}

void displayContacts() {
    printf("Contacts:\n");
    Contact *p = head;
    while (p != NULL) {
        printf("Name: %s\nPhone: %s\n", p->name, p->phone);
        p = p->next;
    }
}

int main() {
    int choice;
    while (1) {
        printf("\nMenu:\n");
        printf("1. Add contact\n");
        printf("2. Delete contact\n");
        printf("3. Search contact\n");
        printf("4. Display all contacts\n");
        printf("5. Exit\n");
        printf("Enter your choice: ");
        scanf("%d", &choice);
        switch (choice) {
            case 1:
                addContact();
                break;
            case 2:
                deleteContact();
                break;
            case 3:
                searchContact();
                break;
            case 4:
                displayContacts();
                break;
            case 5:
                exit(0);
            default:
                printf("Invalid choice\n");
        }
    }
    return 0;
}

该代码使用了无限循环，直到用户选择退出才结束。在每次循环中，根据用户的选择执行相应的操作。