致命错误C1010 - 在Visual Studio中的"stdafx.h"，如何修正？

我编译了下面的代码，但在Visual Studio中出现了一个我无法理解的编译错误。

#include 
using namespace std;
int main()
{
    int matchCount, findResult;
    long childPID;
    string userInput = "blank";
    // string to be searched through
    string longString = "The PPSh-41 is a Soviet submachine gun designed by Georgi Shpagin as an inexpensive, simplified alternative to the PPD-40.";
    while (userInput.compare("!wq"));
    {
        // reset variables for reuse
        matchCount = 0;
        findResult = -1;
        cout << "Please enter a word/s to search for (!wq to exit): "; // prompts user for string to search for cin >> userInput; // takes user input
        if (userInput.compare("!wq")) // checks user input to see if they still wish to search for a string
        {
            childPID = fork();
            if (childPID == 0)
            {
                while (findResult < longString.length)
                {
                    findResult = longString.find(userInput, findResult + 1, userInput.length);
                    if (findResult < longString.length)
                        matchCount++;
                }
                cout << "There are " << matchCount << " instances of " << userInput << " in longString." << endl;
            }
            else
                cout << "childPID != 0" << endl;
        }
        else
            cout << "User has chosen to exit. Exiting." << endl;
    }
    return 0;
}

错误提示如下：

\"wordcount.cpp(57) : fatal error C1010: unexpected end of file while looking for precompiled header. Did you forget to add \'#include \"stdafx.h\"\' to your source?\"

我认为我不需要头文件来运行这段代码。提前感谢您的所有帮助。