Question

确定。所以我有一个任务，加载一个书籍文件和他们的作者顺序行。我已将标题加载到书名列表中，并将书籍作者加入书籍作者数组中。我需要做以下事情。

显示所有书籍和作者。＆LT;＆LT;＆LT;完成。

显示来自用户输入AUTHOR搜索字符串的所有书籍和作者。＆LT;＆LT;半作品

从用户输入BOOK搜索字符串显示所有书籍和作者。＆LT;＆LT;半作品

最后两个有问题

作者功能。

用户输入：Malik

输出：0作者发现！（14次）

标题查询相同。

我已经在网上搜索了一百万次阅读我的书。好吧也许没那么多。尝试了一百个不同版本的代码并且仍在受到伤害。

任何帮助都会很棒！

这是我的代码。

#include <iostream>
#include <string>
#include <fstream>

using namespace std;
//these declarations should be at file scope
const int ARRAY_SIZE = 1000;
string bookTitle  [ARRAY_SIZE];
string bookAuthor [ARRAY_SIZE];
int nob = 0;
ifstream dataBase;


// Function prototypes
int loadData(string pathName);//complete  
void showAll(int nob);
int showBooksByAuthor (int nob, string name);
int showBooksByTitle (int nob, string title);
void showChoices();

int main()
{
    string pathName;
    int x = 1;
    char menu;
    cout << "Welcome to Phil's Library Database. " << endl;
    cout << "Enter the location of the Database: (ex: c:/filename.txt ";
    cin  >> pathName;
    //read pathName and input data to arrays
    dataBase.open(pathName);
    loadData(pathName);
    //output number of files loaded
    cout << nob <<" records loaded successfully." <<endl;

    string name;
    string title;

        while(x == 1)
        {
            //prompt User for what they want to do
            cout << "Enter Q to (Q)uit, Search (A)uthor, Search (T)itle, (S)how All: ";
            cin  >> menu;
            switch(menu)
                {
                case 'Q':
                case 'q':
                    //exit out of program
                    x = 3;
                    break;
                    case 'A':
                case 'a':
                    cout << "Author's Name: ";
                    getline (cin, name, '\n');
                    //list books by author
                    showBooksByAuthor (nob,name);
                    break;
                case 'T':
                case 't':
                    cout << "Book Title: ";
                    getline (cin, title, '\n');
                    showBooksByTitle (nob, title);
                    break;
                case 'S':
                case 's':
                    //cout the entire documents array-ed contents
                    showAll(nob);
                    break;
            }
        }


    system("pause");
    getchar();
    return 0;
}    

int loadData(string pathName)
{
if(dataBase.is_open())
        {
            while(!dataBase.eof())
            {
                getline(dataBase, bookTitle[nob], '\n');
                getline(dataBase, bookAuthor[nob], '\n');
                nob += 1;

            }
        dataBase.clear();
        dataBase.seekg(0);
        return nob;
        }
else 
    cout << "Bad file path!"<< endl;
    return -1;
}
//showall Function
void showAll(int nob)
{
    for (int i = 0; i < nob; i++)
    {
        //show all content of each array
        cout << bookTitle[i]<<endl;
        cout << bookAuthor[i]<<endl;    
    }
}
//showall books based on Author
int showBooksByAuthor (int nob, string name)
{
    int x = 0;
    for(int i = 0; i < nob; i++)
    {
        if (bookAuthor[i].find(name)) 
        {
            //output array location data
            cout << bookTitle[i];
            cout << "(" << bookAuthor[i] << ")" << endl;
            //add onto counter for output of successfully searched items
            x++;
        }
        cout << x << " Records found. " << endl;
    }

    return x;
}

//showall books based on Title
int showBooksByTitle (int nob, string title)
{
    int x = 0;
    for(int i = 0; i < nob; i++)
    {
        if (bookAuthor[i].find(title)) 
        {
            //output array location data
            cout << bookTitle[i];
            cout << "(" << bookAuthor[i] << ")" << endl;
            //add onto counter for output of successfully searched items
            x++;
        }
        cout << x << " Records found. " << endl;
    }

    return x;
}

提前谢谢！

Answer 1

根据此页面http://www.cplusplus.com/reference/string/string/find/和此http://www.cplusplus.com/reference/string/string/npos/，当没有匹配项时，String上的find（）方法返回-1。

只要if ( some_num )非零，

some_num为真，包括-1，其中some_num是任何表达式。

仔细阅读查找文档，了解如何使用它来检查匹配项。

Answer 2

1）不需要find功能。您需要做的就是使用==。

2）对于标题，您应该测试bookTitle数组，而不是bookAuthor。

  int showBooksByAuthor (int nob, string name)
  {
      // ...
      // Search for author
      if ( bookAuthor[i] == name)
      {
        // name found
      }
      // ...
   }

   // Search for title
   int showBooksByTitle (int nob, string title)
   {
      //...
      if (bookTitle[i] == title)
      {
         // title found
      }
      //...
   }

C ++为给定搜索项的用户的每个实例搜索字符串数组。

2 个答案: