c语言实现电话号码查询系统

一个电话号码查询系统可以有以下基本功能：

1. 添加联系人信息，包括姓名、电话号码、地址等。
2. 查询联系人信息，可以通过姓名或电话号码进行查询。
3. 修改联系人信息，包括姓名、电话号码、地址等。
4. 删除联系人信息，可以通过姓名或电话号码进行删除。
5. 显示所有联系人信息。

下面是一个简单的电话号码查询系统的 C 语言实现代码：

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

#define MAX_CONTACTS 100

typedef struct {
    char name[50];
    char phone[20];
    char address[100];
} Contact;

int num_contacts = 0;
Contact contacts[MAX_CONTACTS];

void add_contact() {
    Contact c;
    printf("Enter name: ");
    fgets(c.name, sizeof(c.name), stdin);
    printf("Enter phone number: ");
    fgets(c.phone, sizeof(c.phone), stdin);
    printf("Enter address: ");
    fgets(c.address, sizeof(c.address), stdin);
    contacts[num_contacts++] = c;
    printf("Contact added successfully.\n");
}

void search_contact() {
    char query[50];
    printf("Enter name or phone number to search: ");
    fgets(query, sizeof(query), stdin);
    for (int i = 0; i < num_contacts; i++) {
        if (strstr(contacts[i].name, query) || strstr(contacts[i].phone, query)) {
            printf("Name: %sPhone: %sAddress: %s\n", contacts[i].name, contacts[i].phone, contacts[i].address);
        }
    }
}

void modify_contact() {
    char query[50];
    printf("Enter name or phone number to modify: ");
    fgets(query, sizeof(query), stdin);
    for (int i = 0; i < num_contacts; i++) {
        if (strstr(contacts[i].name, query) || strstr(contacts[i].phone, query)) {
            printf("Enter new name (leave blank to keep existing name): ");
            fgets(contacts[i].name, sizeof(contacts[i].name), stdin);
            printf("Enter new phone number (leave blank to keep existing phone number): ");
            fgets(contacts[i].phone, sizeof(contacts[i].phone), stdin);
            printf("Enter new address (leave blank to keep existing address): ");
            fgets(contacts[i].address, sizeof(contacts[i].address), stdin);
            printf("Contact modified successfully.\n");
        }
    }
}

void delete_contact() {
    char query[50];
    printf("Enter name or phone number to delete: ");
    fgets(query, sizeof(query), stdin);
    for (int i = 0; i < num_contacts; i++) {
        if (strstr(contacts[i].name, query) || strstr(contacts[i].phone, query)) {
            for (int j = i; j < num_contacts - 1; j++) {
                contacts[j] = contacts[j + 1];
            }
            num_contacts--;
            printf("Contact deleted successfully.\n");
            return;
        }
    }
    printf("Contact not found.\n");
}

void display_contacts() {
    for (int i = 0; i < num_contacts; i++) {
        printf("Name: %sPhone: %sAddress: %s\n", contacts[i].name, contacts[i].phone, contacts[i].address);
    }
}

int main() {
    int choice;
    do {
        printf("1. Add contact\n");
        printf("2. Search contact\n");
        printf("3. Modify contact\n");
        printf("4. Delete contact\n");
        printf("5. Display all contacts\n");
        printf("6. Quit\n");
        printf("Enter your choice: ");
        scanf("%d", &choice);
        getchar(); // to consume the newline character left by scanf
        switch (choice) {
            case 1:
                add_contact();
                break;
            case 2:
                search_contact();
                break;
            case 3:
                modify_contact();
                break;
            case 4:
                delete_contact();
                break;
            case 5:
                display_contacts();
                break;
            case 6:
                printf("Goodbye!\n");
                break;
            default:
                printf("Invalid choice.\n");
                break;
        }
    } while (choice != 6);
    return 0;
}

注意，这个实现是非常基础的，仅适用于小规模的电话号码查询。在实际应用中，可能需要处理更多的输入验证、数据存储和并发访问等问题。