變量具有不完整的類型“void”C++

Question

我想出了一個學校作業的解決方案，但我無法編譯它。 我有五個錯誤，我相信它們都源於我沒有正確編寫我的 void 函數。 我仍然是編碼的新手，我無法弄清楚這一點。 幫助將不勝感激，謝謝！

當前代碼：

#include <iostream>
#include <string>
#include <algorithm>


void AddList(LinkedList<char>& List, std::string input)
{
    for (int i = input.size()-1; i >=0; i--)
    {
        List.add(input[i]);
    } // end for loop
} // end ListTester

bool ifSubString(LinkedList<char>& List, std::string input)
{
    std::string fromTheList = List.toString();
        return (fromTheList.find(subString) != std::string::npos);

}

void AppendList(LinkedList<char>& List, std::string input)
{
    List.clear();
    for (int i = input.size()-1; o >=0; i--)
    {
        List.add(input);
    }
}

int main()
{
    std::string userString, newstring, substring;
    int choice;
    char charInput;
    LinkedList<char> listik;

    std::cout << "Welcome to the linkedlist program\n" <<std::endl;
    std::cout << "Please Enter the string before we start: ";
    getline(std::cin, userString);
    AddList(listik, userString);
    std::cout << "The string \"" << userString << "\" has been added to the linked list.\n" << std::endl;
    std::cout << "Menu: " << std::endl;
    std::cout << "1. Find the length of your input." << std::endl;
    std::cout << "2. Add a new string to the current string." << std::endl;
    std::cout << "3. Find the index of the character." << std::endl;
    std::cout << "4. Find matches in the string." << std::endl;
    std::cout << "5. Quit and sleep" << std::endl;
    std::cin >> choice;
    std::cin.ignore();

    while(choice!=5)
    {
        switch(choice)
        {
            case 1:
                std::cout << "The List " << listik.toString() << " contains " << listik.getCurrentSize() << " elements." << std::endl;
                std::cout << std::endl;
                break;
            case 2:
                std::cout << "Please type the string you'd like to append to the current list: ";
                getline(std::cin, newstring);
                Appendlist(listik, (userString+newstring));
                std::cout << "The list is \"" << listik.toString() << "\"." << std::endl; //AppendList function contains add method
                std::cout << std::endl;
                break;
            case 3:
                std::cout << "Please type the character you'd like to have the index of: ";
                std::cin >> charInput;
                std::cout << "The index of \"" << charInput << "\" is " << listik.getFrequencyOf(charInput) << std::endl;
                std::cout << std::endl;
                break;
            case 4:
                std::cout << "Please type the string you'd like to find in the current list:  ";
                getline(std::cin, subString);
                std::cout << "The string \"" << subString << "\" is";
                if (ifSubString(listik, subString)==false) std::cout << " not";
                std::cout << "found in \"" << listik.toString() << "\"." << std::endl;
                std::cout << std::endl;
                break;
            case 5:
                listik.clear();
                exit(0);
                break;
        }
    }
}

Answer 1

我認為你復制了一份作業並在途中引入了一堆錯別字。 您需要填寫作業中的空白並實現類模板LinkedList 。

這是您已刪除拼寫錯誤的作業，您需要實現LinkedList成員函數：

#include <iostream>
#include <string>
#include <algorithm>

template<class T>
struct LinkedList {
    void add(T element);
    std::string toString() const;
    void clear();
    int getCurrentSize() const;
    int getFrequencyOf(T element) const;
};

void AddList(LinkedList<char>& List, std::string input)
{
    for (int i = input.size()-1; i >=0; i--)
    {
        List.add(input[i]);
    } // end for loop
} // end ListTester

bool ifSubString(LinkedList<char>& List, std::string input)
{
    std::string fromTheList = List.toString();
    return (fromTheList.find(input) != std::string::npos);

}

void AppendList(LinkedList<char>& List, std::string input)
{
    List.clear();
    for (int i = input.size()-1; i >=0; i--)
    {
        List.add(input[i]);
    }
}

int main()
{
    std::string userString, newstring, subString;
    int choice;
    char charInput;
    LinkedList<char> listik;

    std::cout << "Welcome to the linkedlist program\n" <<std::endl;
    std::cout << "Please Enter the string before we start: ";
    getline(std::cin, userString);
    AddList(listik, userString);
    std::cout << "The string \"" << userString << "\" has been added to the linked list.\n" << std::endl;
    std::cout << "Menu: " << std::endl;
    std::cout << "1. Find the length of your input." << std::endl;
    std::cout << "2. Add a new string to the current string." << std::endl;
    std::cout << "3. Find the index of the character." << std::endl;
    std::cout << "4. Find matches in the string." << std::endl;
    std::cout << "5. Quit and sleep" << std::endl;
    std::cin >> choice;
    std::cin.ignore();

    while(choice!=5)
    {
        switch(choice)
        {
            case 1:
                std::cout << "The List " << listik.toString() << " contains " << listik.getCurrentSize() << " elements." << std::endl;
                std::cout << std::endl;
                break;
            case 2:
                std::cout << "Please type the string you'd like to append to the current list: ";
                getline(std::cin, newstring);
                AppendList(listik, (userString+newstring));
                std::cout << "The list is \"" << listik.toString() << "\"." << std::endl; //AppendList function contains add method
                std::cout << std::endl;
                break;
            case 3:
                std::cout << "Please type the character you'd like to have the index of: ";
                std::cin >> charInput;
                std::cout << "The index of \"" << charInput << "\" is " << listik.getFrequencyOf(charInput) << std::endl;
                std::cout << std::endl;
                break;
            case 4:
                std::cout << "Please type the string you'd like to find in the current list:  ";
                getline(std::cin, subString);
                std::cout << "The string \"" << subString << "\" is";
                if (ifSubString(listik, subString)==false) std::cout << " not";
                std::cout << "found in \"" << listik.toString() << "\"." << std::endl;
                std::cout << std::endl;
                break;
            case 5:
                listik.clear();
                exit(0);
                break;
        }
    }
}

閱讀編譯器錯誤消息，它們會告訴您出了什么問題。