正在搜索鏈接的列表C++

Question

所以我的項目是有一個隨機數猜測遊戲（1-100），並將用戶的猜測值存儲到鏈表中。我有的難題是用已存儲在鏈表中的先前輸入檢查用戶的當前輸入。我無法弄清楚爲什麼它會一直告訴我，我真的沒有猜到過以前的數字。

#include <iostream> 
#include <iomanip> 
#include <ctime> 
#include <cstdlib> 
using namespace std; 

struct Guess 
{ 
    int numberGuess; 
    Guess* next; 
}; 

int main() 
{ 
    srand(time(0)); 

    Guess* start = 0; 

    //Defining variables 
    int randomNumber; 
    randomNumber = (rand() % 100) + 1; 
    int userGuess; 
    int i = 0; 

    Guess* userValue = new Guess; 

    cout << "I'm thinking of a number between 1 and 100. Guess what it is: " << endl; 
    cin >> userGuess; 
    cin.ignore(1000,10); 

    userValue->numberGuess = userGuess; 
    userValue->next = start; 
    start = userValue; 

    while(true) 
    { 
     if (userGuess > randomNumber) 
     { 
      cout << "That's too high, guess again: "; 
      cin >> userGuess; 
      cin.ignore(1000,10); 

      //Pass user's guess to linked based list 
      Guess* userValue = new Guess; 
      userValue->numberGuess = userGuess; 
      userValue->next = start; 
      start = userValue; 
     } 

     else if(userGuess < randomNumber) 
     { 
      cout << "That's too low, guess again: "; 
      cin >> userGuess; 
      cin.ignore(1000,10); 

      //Pass user's guess to linked based list 
      Guess* userValue = new Guess; 
      userValue->numberGuess = userGuess; 
      userValue->next = start; 
      start = userValue; 
     } 

     if (userGuess == randomNumber) 
     { 
      cout << "Correct!" << endl; 
      break; 
     } 

     //Check to see if it has been guessed 
     bool checkDuplicate = false; 
     Guess* p; 
     for (p = start; p; p = p->next) 
     { 
      if (p->numberGuess == userGuess) 
      {    
       checkDuplicate = true; 
       break; 
      } 
     } 

     if (checkDuplicate == true) 
     { 
      cout << "You already guessed that value! -- Guess again: "; 
      cin >> userGuess; 
      cin.ignore(1000,10); 
     } 
    } 
} 

任何想法？

Answer 1

當用戶輸入他們的猜測時，將其添加到列表中，然後嘗試找到它。因爲你已經添加了它，所以每次都可以在列表中找到猜測。所以，你需要移動節點的代碼添加到循環的末尾，例如這裏

if (checkDuplicate == true) { 
     cout << "You already guessed that value! -- Guess again: "; 
     cin >> userGuess; 
     cin.ignore(1000,10); 
    } else { 
     Guess* userValue = new Guess; 
     userValue->numberGuess = userGuess; 
     userValue->next = start; 
     start = userValue; 
    } 

還將創建列表操作功能，如add_node，或exist，代碼將是簡單明瞭。看看例子

#include <iostream> 
#include <iomanip> 
#include <ctime> 
#include <cstdlib> 
using namespace std; 

struct Guess { 
    int numberGuess; 
    Guess* next; 
}; 

bool exist(Guess* start, int number) { 
    for (Guess* p = start; p != NULL; p = p->next) { 
     if (p->numberGuess == number) { 
      return true; 
     } 
    } 
    return false; 
} 

void print(Guess* start) { 
    for (Guess* p = start; p != NULL; p = p->next) { 
     cout << p->numberGuess << " "; 
    } 
    cout << endl; 
} 

void add(Guess** start, int number) { 
    Guess* userValue = new Guess; 
    userValue->numberGuess = number; 
    userValue->next = *start; 
    *start = userValue; 
} 

int main() { 
    srand(time(0)); 

    Guess* start = 0; 

    //Defining variables 
    int randomNumber; 
    randomNumber = (rand() % 100) + 1; 
    int userGuess; 

    cout << "I'm thinking of a number between 1 and 100. Guess what it is: " << endl; 
    while(true) 
    { 
     cin >> userGuess; 
     cin.ignore(1000, '\n'); 
     if (userGuess > randomNumber) { 
      cout << "That's too high, guess again: "; 
     } 
     else if(userGuess < randomNumber) { 
      cout << "That's too low, guess again: "; 
     } 
     if (userGuess == randomNumber) { 
      cout << "Correct!" << endl; 
      cout << "Your previous guesses was: "; 
      print(start); 
      break; 
     } 
     //Check to see if it has been guessed 
     bool checkDuplicate = exist(start, userGuess); 
     if (checkDuplicate == true) { 
      cout << "You already guessed that value! -- Guess again: "; 
     } else { 
      add(&start, userGuess); 
     } 
    } 
} 

現在很明顯，main發生了什麼，很容易讀，也沒有重複代碼，就像是之前。也不要在你的程序中使用符號代碼，使用符號（在你的情況下'\n'）。