如何使用其他值對空格進行冒泡排序？

Question

我想從用戶那裏得到一個輸入，並對該輸入進行冒泡排序然後輸出結果。我的代碼：

#include<iostream> 
    using namespace std; 
    class bubble 
    { 
    public : 

     string arr[20]; 

     //Number of elements in array 
     int n; 

     //Function to accept array elements 
     void read() 
     { 
      while(1) 
      { 
       cout<<"\nEnter the number of elements in the array:"; 
       cin>>n; 
       if(n<=20) 

        break; 
       else 
        cout<<"\n Array can have maximum 20 elements \n"; 
      } 
      //display the header 
      cout<<"\n"; 
      cout<<"----------------------\n"; 
      cout<<"Enter array elements \n"; 
      cout<<"----------------------\n"; 

      //Get array elements 
      for(int i=0; i<n ;i++) 
      { 
       cout<<"<"<<i+1<<"> "; 
       cin>>arr[i]; 
      } 
     } 
     //Bubble sort function 
     void bubblesort() 
     { 
      for(int i=1;i<n ;i++)//for n-1 passes 
      { 
       //In pass i,compare the first n-i elements 
       //with their next elements 
       for(int j=0; j<n-1; j++) 
       { 
        if(arr[j] > arr[j+1]) 
        { 
         string temp; 
         temp = arr[j]; 
         arr[j] = arr[j+1]; 
         arr[j+1] = temp; 

        } 

       } 
      } 
     } 
     void display() 
     { 
      cout<<endl; 
      cout<<"----------------------\n"; 
      cout<<"Sorted array elements \n"; 
      cout<<"----------------------\n"; 
      for(int j=0; j<n; j++) 
       cout<<arr[j]<<endl; 
     } 
}; 
int main() 
{ 
    //Instantiate an instance of class 
    bubble list; 
    // Function call to accept array elements 
    list.read(); 
    // Function call to sort array 
    list.bubblesort(); 
    //Function call to display the sorted array 
    list.display(); 
    return 0; 
} 

代碼運行良好，但它不接受字符串中的空格或縮進值作爲輸入。有沒有辦法讓它接受這些值？

Answer 1

更換>>與std::getline，它可以讓你讀取包含空格的字符串：

// Extract the \n that's left from entering n 
getline(cin, arr[0]); // We'll read it again in the loop 
for(int i=0; i<n ;i++) 
{ 
    cout<<"<"<<i+1<<"> "; 
    getline(cin, arr[i]); 
} 

Answer 2

使用std::getline和std::vector<std::string>。只要用戶不輸入空行，就可以讀取行。

#include <iostream> 
#include <string> 
#include <vector> 

int main() 
{ 
    std::vector<std::string> strings; 

    std::string line; 
    bool user_wants_to_quit = false; 
    while (!user_wants_to_quit && std::getline(std::cin, line)) 
    { 
     if (!line.empty()) 
     { 
      strings.push_back(line); 
     } 
     else 
     { 
      user_wants_to_quit = true; 
     } 
    } 

    std::cout << "Lines:\n"; 
    for (std::vector<std::string>::const_iterator iter = strings.begin(); iter != strings.end(); ++iter) 
    { 
     std::cout << *iter << "\n"; 
    } 
} 

Answer 3

可以使用std::getline從流中讀出所有令牌：

//Get array elements 
getline(cin, arr[0]); 
for(int i = 0; i < n ; ++i) 
{ 
    cout << "<" << i+1 << "> "; 
    getline(cin, arr[ i]); 
}