#include <iostream>

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;
}

Project Properties -> C++ -> Precompiled Headers

#include <stdafx.h>