Can anyone tell me why these functions are not giving me a result in a reasonable spectrum?

问题

The full code I am using is listed below, it is supposed to simulate a game of craps and print details to the user and allow for betting if the user desires it. Everything functions except for the actual craps game. Instead of looping only while there is not a truth value associated to crapsResult, it finds one real value and an incomprehensible string of a single negative number. Any help would be appreciated.

int main()
{
    //Declare the user input variables
    int gamesPlayed = 0;
    char inputPrint = ' ';
    char isBetting = ' ';
    int startingBet = 0;

    //Declare the variables used by the program
    int endingBet = 0;
    int currentGame = 0;
    bool crapsResult;
    int gamesWon = 0;
    int gamesLost = 0;
    double percentWon = 0;
    bool detailPrint = false;

    //Prompt the user to input their variables
    cout << "Enter the number of games to be played: ";
    cin >> gamesPlayed;
    while(gamesPlayed < 1)
    {
        cout << "   Error: must be greater than 0" << endl;
        cout << "Enter the number of games to be played: ";
        cin >> gamesPlayed;
        cin.clear();
        cin.ignore();
    }

    cout << "Do you wish to print details (Y/N): ";
    cin >> inputPrint;
    if(inputPrint == 'y' || inputPrint == 'Y')
    {
        detailPrint = true;
    }

    cout << "Do you wish to bet (Y/N): ";
    cin >> isBetting;

    if(isBetting == 'y' || isBetting == 'Y')
    {
        cout << "Enter money to start betting with: ";
        cin >> startingBet;
        while(startingBet < 1)
        {
            cout << "   Error: must be greater than 0" << endl;
            cout << "Enter the number of games to be played: ";
            cin >> gamesPlayed;
            cin.clear();
            cin.ignore();
        }
    }
    //Seed the random number generator
    srand(time(NULL));

    //Set a value for ending bet
    if(startingBet == 0)
    {
        endingBet = 1;
    }
    else
    {
        endingBet = startingBet;
    }
    //Call playcraps to simulate the game for as many games as the user input
    for(currentGame = 1; currentGame <= gamesPlayed && endingBet > 0; currentGame += 1)
    {
        crapsResult = NULL;
        crapsResult = playCraps(currentGame, detailPrint, isBetting, startingBet);
        if(crapsResult == true)
        {
            gamesWon += 1;
            endingBet = betting(endingBet, crapsResult);
        }
        if(crapsResult == false)
        {
            gamesLost += 1;
            endingBet = betting(endingBet, crapsResult);
        }
        if((isBetting == 'Y' || isBetting == 'y') && (detailPrint == true))
        {
            cout << "Money left is $" << endingBet << endl;
        }
    }

    //Calculate the percentage of games won
    percentWon = (double(gamesWon) / double(currentGame-1)) * 100.0;

    //Print the results to the user
    if(isBetting == 'Y' || isBetting == 'y')
    {
        cout << "Money at end of games is $" << endingBet << endl;
    }
    cout << "The number of games played is " << currentGame - 1 << endl;
    cout << "The number of games won is " << gamesWon << endl;
    cout << "The number of games lost is " << gamesLost << endl;
    cout << "The percent of games won is " << fixed << showpoint << setprecision(3) << percentWon << endl;
}

//Simulates the roll of a single die and returns the result
int roll()
{
    int rollResult = 0;
    rollResult = rand() % 6 + 1;
    return rollResult;
}

//Calls roll twice and returns the sum of the two results
int roll2Dice()
{
    //Declare variables for this function
    int rollOne = 0;
    int rollTwo = 0;
    int rollSum = 0;

    //Find rollOne and rollTwo
    rollOne = roll();
    rollTwo = roll();

    //Find rollSum
    rollSum = rollOne + rollTwo;

    return rollSum;
}

bool playCraps(int currentGame, bool detailPrint, char isBetting, int startingBet)
{
    bool crapsResult = NULL;
    int currentGameStorage[100];
    int currentRoll = 1;
    int point = roll2Dice();
    int printingNumber = 0;
    currentGameStorage[0] = point;
    if(point == 7 || point == 11)
    {
        crapsResult = true;
    }
    else if(point == 2 || point == 3 || point == 12)
    {
        crapsResult = false;
    }
    else
    {
        crapsResult = NULL;
    }
    while(crapsResult != true && crapsResult != false)
    {
        currentGameStorage[currentRoll] = roll2Dice();
        if(currentGameStorage[currentRoll] == point)
        {
            crapsResult = true;
        }
        else if(currentGameStorage[currentRoll] == 7)
        {
            crapsResult = false;
        }
        currentRoll += 1;
    }
    if(detailPrint == true)
    {
        cout << "Game " << currentGame << ": ";
        for(printingNumber = 0; printingNumber <= currentRoll; printingNumber += 1)
        {
            cout << currentGameStorage[printingNumber] << " ";
        }
        if(crapsResult == true)
        {
            cout << "win";
        }
        else if(crapsResult == false)
        {
            cout << "lose";
        }
        cout << endl;
    }
    return crapsResult;
}

int betting(int endingBet, bool crapsResult)
{
    if(crapsResult == true)
    {
        endingBet += 1;
    }
    else if(crapsResult == false)
    {
        endingBet -= 1;
    }
    return endingBet;
}

回答1:

Just skimmed and didn't read all of your code (so there may be other things wrong too), but this line is definitely problematic:

while(crapsResult != true && crapsResult != false)

It is logically impossible for crapsResult to simultaneously be both true and false, so that loop will never be entered.

回答2:

Turix got the right bug I believe, but I would put the emphasis on a different spot:

bool crapsResult = NULL;

You are trying to use crapsResult for three different values (true, false and NULL). However, NULL usually has a integer value of 0, which translates to a boolean value of false, so your loop will never be entered.

Then a second bug comes into play: currentRoll is 1 at this time, so you try to print the contents of currentGameStorage from index 0 to 1 (inclusive), currentGameStorage[1] hasn't been assigned yet. This is why you get the cryptic numer in your output. This is a general mistake: Your code always tries to print one item too much. Use < instead of <= in the loop head to fix that:

for(printingNumber = 0; printingNumber < currentRoll; printingNumber += 1)

来源：https://stackoverflow.com/questions/19719454/can-anyone-tell-me-why-these-functions-are-not-giving-me-a-result-in-a-reasonabl