搜索字符串数组 [英] Searching a array of strings

问题描述

基本上，此程序的目的是从文件中读取多达100个名称，使用bubblesort排序，然后通过二分搜索搜索输入的名称。

所有似乎都工作，除非当我输入一个名称，在列表中，没有什么发生，我只是提示输入一个名称。

在Elvis Presley的名单中说出名字。我被提示输入一个名称。我输入Elvis Presley。我应该收到埃尔维斯·普雷斯利是你的朋友。不发生。任何帮助赞赏。

  #include< iostream> 
 #include< fstream> 
 #include< string> 
 using namespace std; 
 
 void bubblesort（string []，const int）; 
 void search（string []，const int）; 
 int sub = 0; 
 
 int main（）
 {
 const int maxsize = 100; 
 string friendArray [maxsize]; 
 
 ifstream friends; 
 friends.open（myFriends.dat）; 
 
 while（sub< maxsize&& getline（friends，friendArray [sub]））
 sub ++; 
 
 
 bubblesort（friendArray，sub）; 
 search（friendArray，maxsize）; 
 
 
系统（暂停）; 
 return 0; 
} 
 
 
 
 void bubblesort（string * array，const int size）
 {
 bool swap; 
 string temp; 
 
 do 
 {
 swap = false; 
 for（int count = 1; count<（size-1）; count ++）
 {
 if（array [count-1]> array [count]）
 {
 temp = array [count-1]; 
 array [count-1] = array [count]; 
 array [count] = temp; 
 swap = true; 
} 
} 
} 
 while（swap）; 
 
} 
 
 void search（string * array，int size）
 {
 int first = 0; 
 int last = size  -  1; 
 int middle; 
 string name; 
 bool friends = false; 
 
 do 
 {
 cout<<请输入名称或END以终止：; 
 cin>> name; 
} 
 while（！friends&&& first< = last&& name！=END）; 
 {
 middle =（first + last）/ 2; 
 if（array [middle] == name）
 {
 friends = true; 
 cout<< array [middle]<<是我的朋友。<<< endl; 
} 
 else if（array [middle]> name）
 last = middle  -  1; 
 else 
 last = middle + 1; 
} 
} 
  

解决方案你的 search（）函数， do {} while; {} 构造有缺陷。它会编译，但它不会做你想要的。我做了一些更改，并重新安排你的代码，所以它更有意义。

  void search（string * array，int size）
 {
字符串名称; 
 
 for（;;）
 {
 cout<<请输入名称或END以终止：; 
 getline（cin，name）; 
 if（name ==END）break; 
 
 int first = 0; 
 int last = size  -  1; 
 bool friends = false; 
 
 while（！friends&& first< = last）
 {
 int middle =（first + last）/ 2; 
 if（array [middle] == name）
 {
 friends = true; 
 cout<< array [middle]<<是我的朋友。<<< endl; 
} 
 else if（array [middle]> name）
 last = middle  -  1; 
 else 
 first = middle + 1; 
} 
} 
} 
 
 int main（）//测试search（）函数
 {
 string array [] = { bird，cat，dog，horse，loon，zebra}; 
 search（array，6）; 
} 
  

我应该删除吗？

Basically the purpose of this program is to read up to 100 names from file, sort with a bubblesort, and then search for a entered name by binary search.

All seems to be working except when I enter a name that is in the list, nothing happens, I'm just prompted to enter a name again.

Say a name in the list in Elvis Presley. I am prompted to enter a name. I type in Elvis Presley. I SHOULD recieve Elvis Presley is your friend. Not happening. Any help appreciated.

#include <iostream>
#include <fstream>
#include <string>
using namespace std;

void bubblesort(string[], const int);
void search(string[], const int);
int sub = 0;

int main()
{
 const int maxsize = 100;
 string friendArray[maxsize];

 ifstream friends;
 friends.open("myFriends.dat");

 while (sub < maxsize && getline(friends, friendArray[sub]))
   sub++;


 bubblesort(friendArray, sub);
 search(friendArray, maxsize);


 system("pause");
 return 0;
}



void bubblesort(string *array, const int size)
{
    bool swap;
    string temp;

    do
    {
        swap = false;
        for (int count = 1; count < (size - 1); count++)
        {
            if(array[count-1] >array[count])
            {
                temp = array[count-1];
                array[count-1] = array[count];
                array[count] = temp;
                swap = true;
            }
        }
    }
    while(swap);

}

void search(string *array, int size)
{
    int first = 0;
    int last = size - 1;
    int middle;
    string name;
    bool friends = false;

    do
    {
     cout<<"Please enter a name or END to terminate:";
     cin>>name;
    }
    while(!friends && first <= last && name != "END");
    {
        middle = (first + last) / 2;
        if (array[middle] == name)
            {
                friends = true;
                cout<<array[middle]<<" is my friend."<<endl;
            }
        else if (array[middle] > name)
            last = middle - 1;
        else
            last = middle + 1;
    }
}

解决方案

In your search() function, the do { } while; { } construct is flawed. It will compile but it doesn't do what you want. I made a few changes and rearranged your code so it makes more sense.

void search(string *array, int size)
{
    string name;

    for (;;)
    {
        cout<<"Please enter a name or END to terminate:";
        getline(cin, name);
        if (name == "END") break;

        int first = 0;
        int last = size - 1;
        bool friends = false;

        while (!friends && first <= last)
        {
            int middle = (first + last) / 2;
            if (array[middle] == name)
            {
                friends = true;
                cout<<array[middle]<<" is my friend."<<endl;
            }
            else if (array[middle] > name)
                last = middle - 1;
            else
                first = middle + 1;
        }
    }
}

int main () // test the search() function
{
    string array[] = { "bird", "cat", "dog", "horse", "loon", "zebra" };
    search(array, 6);
}

SO, is this too much homework help? Should I delete this?

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