#include <iostream> #include <cstring> using namespace std; class Book { public: string title; string author; string publisher; string date; Book(string t, string a,string p,string d) { title=t; author=a; publisher=p; date=d; } ~Book(){} }; class Library { public: Book book[100]; int n; Library(){n=0;} void AddBook(Bookb) { book[n++]=b; } void DeleteBook(string t) { for (int i=0;i<n;i++) { if(book[i]->title==t) { delete book[i]; book[i]=NULL; for(int j=i;j<n-1;j++) { book[j]=book[j+1]; } n--; } } cout<<"未找到题目为"<<t<<"的书籍"<<endl; } void ShowBook() { cout<<"书籍显示"<<endl; for(int i=0;i<n;i++) { cout<<book[i]->title<<" "<<book[i]->author<<" "<<book[i]->publisher<<" "<<book[i]->date<<endl; } } BookFindBook(string t) { for (int i=0;i<n;i++) { if(book[i]->title==t) { return book[i]; } } cout<<"未找到题目为"<<t<<"的书籍"<<endl; return NULL; } ~Library() { for(int i=0;i<n;i++) { delete book[i]; } } }; int main() { Library l; int input; string t,a,p,d; cout << "------------------菜单栏------------------" << endl; cout << "1.图书信息添加" << endl; cout << "2.图书信息删除" << endl; cout << "3.图书信息查看" << endl; cout << "4.图书信息查找" << endl; cout << "0.退出" << endl; while(1) { cout << "请选择功能" << endl; cin >> input; switch (input) { case 1: { cout<<"请输入添加的图书书名："; cin>>t; cout<<"请输入添加的图书作者："; cin>>a; cout<<"请输入添加的图书出版社："; cin>>p; cout<<"请输入添加的图书出版日期："; cin>>d; Bookb=new Book(t,a,p,d); l.AddBook(b); break; } case 2: { cout<<"请输入删除的图书书名："; cin>>t; l.DeleteBook(t); break; } case 3: { l.ShowBook(); break; } case 4: { cout<<"请输入查找的图书书名："; cin>>t; Book *b=l.FindBook(t); if(b!=NULL) { cout<<"查询结果为："<<b->title<<" "<<b->author<<" "<<b->publisher<<" "<<b->date<<endl; } break; } case 0: { cout<<"已退出"<<endl; return 0; } } } }优化这段程序

这段程序可以进行如下的优化：

1. 对输入进行错误处理，避免输入非法字符导致程序崩溃。

2. 在 Library 类中添加一个私有成员变量 max_len，表示 book 数组的最大长度，避免数组越界的错误。

3. 在 AddBook 方法中，当 book 数组已满时需要进行扩容。

4. 在 DeleteBook 和 FindBook 方法中，可以使用引用来避免对对象进行拷贝，提高程序效率。

5. 修改 ShowBook 方法的输出格式，让输出更加美观。

下面是修改后的程序：

#include <iostream> 
#include <cstring> 

using namespace std;

class Book {
public:
    string title;
    string author;
    string publisher;
    string date;

    Book(string t, string a, string p, string d) {
        title = t;
        author = a;
        publisher = p;
        date = d;
    }

    ~Book() {}
};

class Library {
private:
    Book* book;
    int n;
    int max_len;

public:
    Library() {
        n = 0;
        max_len = 100;
        book = new Book[max_len];
    }

    void AddBook(Book& b) {
        if (n >= max_len) {
            max_len *= 2;
            Book* new_book = new Book[max_len];
            memcpy(new_book, book, n * sizeof(Book));
            delete[] book;
            book = new_book;
        }

        book[n++] = b;
    }

    void DeleteBook(string t) {
        for (int i = 0; i < n; i++) {
            if (book[i].title == t) {
                for (int j = i; j < n - 1; j++) {
                    book[j] = book[j + 1];
                }
                n--;
                return;
            }
        }

        cout << "未找到题目为 " << t << " 的书籍" << endl;
    }

    void ShowBook() {
        cout << "------------------书籍显示------------------" << endl;
        cout << "书名\t\t作者\t\t出版社\t\t出版日期" << endl;
        for (int i = 0; i < n; i++) {
            cout << book[i].title << "\t\t" << book[i].author << "\t\t" << book[i].publisher << "\t\t" << book[i].date << endl;
        }
    }

    Book& FindBook(string t) {
        for (int i = 0; i < n; i++) {
            if (book[i].title == t) {
                return book[i];
            }
        }

        cout << "未找到题目为 " << t << " 的书籍" << endl;
        static Book null_book("", "", "", "");
        return null_book;
    }

    ~Library() {
        if (book) {
            delete[] book;
        }
    }
};

int main() {
    Library l;
    int input;
    string t, a, p, d;

    cout << "------------------菜单栏------------------" << endl;
    cout << "1.图书信息添加" << endl;
    cout << "2.图书信息删除" << endl;
    cout << "3.图书信息查看" << endl;
    cout << "4.图书信息查找" << endl;
    cout << "0.退出" << endl;

    while (1) {
        cout << "请选择功能: ";
        cin >> input;

        switch (input) {
            case 1: {
                cout << "请输入添加的图书书名：";
                cin >> t;
                cout << "请输入添加的图书作者：";
                cin >> a;
                cout << "请输入添加的图书出版社：";
                cin >> p;
                cout << "请输入添加的图书出版日期：";
                cin >> d;
                Book b(t, a, p, d);
                l.AddBook(b);
                break;
            }

            case 2: {
                cout << "请输入删除的图书书名：";
                cin >> t;
                l.DeleteBook(t);
                break;
            }

            case 3: {
                l.ShowBook();
                break;
            }

            case 4: {
                cout << "请输入查找的图书书名：";
                cin >> t;
                Book& b = l.FindBook(t);
                if (b.title != "") {
                    cout << "查询结果为：" << b.title << "\t\t" << b.author << "\t\t" << b.publisher << "\t\t" << b.date << endl;
                }
                break;
            }

            case 0: {
                cout << "已退出" << endl;
                return 0;
            }

            default: {
                cout << "输入错误，请重新选择功能" << endl;
                break;
            }
        }
    }
}