在循环内夹紧 integer 的问题

Question

I'm really at a loss. I've sat here for hours trying to figure out what's wrong but I just can't see it.

So I have an array that holds integers, named xpData[]. It's used to keep track of how much XP is needed to "level up". It's a member variable of a class Player. I utilize this within a member function of that same class named AddXP().

Within said function, I add the function argument to the member variable xp. This works perfectly fine. It even clamps when hitting the maxExp integer. I've tried the function with just these statements as well, and the problem was "solved" (although it created another problem).

The problem is that I go on to, within the same function, utilize a while loop that checks the xp variable against the xpData[lvl] element. Whenever the xp of the Player is greater than or equal to xpData[lvl], it increments the lvl variable. The issue is that there are a limited number of levels. The maximum being 30, and the minimum 1. So I utilize a clamping function. Below is the code:

GeneralFunctions.cpp

int ClampInt(int n, int lower, int upper)
{
    int updatedNum = n;

    if (n <= lower)
        updatedNum = lower;
    else if (n >= upper)
        updatedNum = upper;

    return updatedNum;
}

Player.h

class Player
{
public:
    Player();

    void AddXP(int amount);

    int GetLevel() const { return lvl; };
    int GetXP() const { return xp; };

private:
    int minLevel;
    int maxLevel;
    int lvl;
    int maxExp;
    int xp;
    int xpData[31] = {
        0,   // zero-based
        10,  // Level 1
        20,  // Level 2
        30,  // Level 3
        40,  // Level 4
        50,  // Level 5
        60,  // Level 6
        70,  // Level 7
        80,  // Level 8
        90,  // Level 9
        100, // Level 10
        110, // Level 11
        120, // Level 12
        130, // Level 13
        140, // Level 14
        150, // Level 15
        160, // Level 16
        170, // Level 17
        180, // Level 18
        190, // Level 19
        200, // Level 20
        210, // Level 21
        220, // Level 22
        230, // Level 23
        240, // Level 24
        250, // Level 25
        260, // Level 26
        270, // Level 27
        280, // Level 28
        290, // Level 29
        300  // Level 30
    };
};

Player.cpp

Player::Player()
{
    minLevel = 1;
    maxLevel = 30;
    lvl = 1;
    maxExp = 1000000;
    xp = 0;
}

void Player::AddXP(int amount)
{
    if (xp + amount > maxExp)
        xp += (maxExp - xp);
    else
        xp += amount;

    while (xp >= xpData[lvl])
    {
        lvl = ClampInt(lvl + 1, minLevel, maxLevel);
    }
}

The issue is that when the xp reaches above the xp required for "level 30", the program just kinda... freezes. No errors, no crashes, nothing. Just freezing. I assume is has something to do with the loop obviously, but I have no clue what to do to fix it, without giving up much needed functionality (ie clamping the levels, or checking within a loop in case the xp added is ever enough to level the player up multiple times, etc.).

Thanks for any help!

Answer 1

Within the loop

while (xp >= xpData[lvl])
    {
        lvl = ClampInt(lvl + 1, minLevel, maxLevel);
    }

the ClampInt function limits lvl to 30 and the while condition keeps beeing satisfied so it loops forever.

Maybe you should just get rid of the ClampInt function and simply use

while(lvl < 30 && xp >= xpData[lvl])
   ++lvl;

Or you could define a level 31 with an XP of INT_MAX which should not be reached