拆分句子和檢索特定單詞

Question

我已經成功地寫出下面的代碼：

#include <iostream> 
#include <vector> 
#include <string> 
using namespace std;  
int main() 
{ 
    string sentence; 
    getline(cin, sentence); 
    char* ptr = &sentence[0]; 
    while (*ptr != '\0'){ 
     if (*ptr == ' '){ 
      cout << endl; 
     } 
     else{ 
      cout << *ptr; 
     } 
     ptr++; 
    } 
} 

使用，我可以單獨打印一個句子的每個單詞。不過，我想存儲它們，然後檢索它們。下面是一個示例運行：

Enter the sentence:This is a sample sentence. 
Which word do you want to see ?:4 
sample 

我不知道如何從上面的代碼繼續。我認爲將每個字母存儲在char數組中，然後將這些數組轉換爲字符串並將它們存儲在vector<string>中，但無法弄清楚。

我想這樣做只使用給定的庫，如果可能的話，不使用任何分割函數。

編輯：這是我最近試過的。雖然沒有工作。

#include <iostream> 
#include <vector> 
#include <string> 
using namespace std; 
int main() 
{ 
    char letter; 
    vector<string> words; 
    vector<char> temp; 
    vector<char> sentence; 
    while(cin >> letter){ // ctrl-z to break 
     sentence.push_back(letter); 
    } 
    char* ptr = &sentence[0]; 
    while (*ptr != '\0'){ 
     while (*ptr != ' '){ 
      temp.push_back(*ptr); 
      ptr++; 
     } 
     words.push_back(str(temp)); 
    } 

}

EDIT2：這裏是用sstream

#include <iostream> 
#include <string> 
#include <sstream> 
#include <vector> 
using namespace std; 
int main() 
{ 
    cout << "Sentence: " << endl; 
    string sentence; 
    getline(cin, sentence); 
    istringstream sin(sentence); 
    vector<string> tokens; 
    string word; 
    while (!sin.eof()){ 
     sin >> word; 
     tokens.push_back(word); 
    } 
    cout << "Which word ?: " << endl; 
    int n; 
    cin >> n; 
    cout << tokens[n - 1] << endl; 
} 

EDIT3的解決方案：儀式，得到了it.Here就是我想要的解決方案。

#include <iostream> 
#include <string> 
using namespace std; 
int wordbyword(string sentence, char** words) 
{ 
    int i = 0, j = 0, k = 0; 
    while (sentence[i] != '\0'){ 
     if (sentence[i] != ' '){ 
      words[j][k] = sentence[i]; 
      k++; 
     } 
     else { 
      j++; 
      k = 0; 
     } 
     i++; 

    } 
    return j; 
} 

    int main() 
    { 
     string sentence; 
     cout << "Sentence: "<< endl; 
     getline(cin, sentence); 
     int size = sentence.length(); 
     char** words = new char*[size]; 
     for (int i = 0; i < size; i++) 
      words[i] = new char[size]; 

     int wordCount = wordbyword(sentence, words) + 1;  
     while(1){ 
      cout << "Word number: " << endl; 
      int n; 
      cin >> n; 
      if (n == 0){ 
       cout << "Terminating..." << endl; 
       break; 
      } 
      else if (n > wordCount || n < 0) 
       cout << "Word doesn't exist" << endl; 
      else 
       cout << words[n - 1] << endl; 
      } 

    } 

Answer 1

你要複製的載體：

istringstream iss(sentence); 
vector<string> tokens; 
copy(istream_iterator<string>(iss), 
    istream_iterator<string>(), 
    back_inserter<vector<string> >(tokens)); 

Answer 2

這其實很簡單。你需要設置一個循環，這個循環在輸入時會運行。對於每次迭代，你應該再push_back到矢量新的字符串：

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

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

    while (std::cin >> word) 
    { 
     words.push_back(word); 
    } 

    int idx = 0; 

    std::cout << "Which word do you want to see? "; 
    std::cin >> idx; 

    std::cout << words[idx]; 
}