限制价值

Question

我有一个小脚本，它定义了这个小项目中所有类的投射时间，但是我有一些问题。

我想在最大值上设置上限，但是我收到了错误！

这是我所指的功能。

   void Player::ApplyRatingMod(CombatRating combatRating, int32 value, bool apply)
{
    float oldRating = m_baseRatingValue[combatRating];
    m_baseRatingValue[combatRating] += (apply ? value : -value);

    // explicit affected values
    float const multiplier = GetRatingMultiplier(combatRating);
    float const oldVal = oldRating * multiplier;
    float const newVal = m_baseRatingValue[combatRating] * multiplier;

    switch (combatRating)
    {
        case CR_HASTE_MELEE:
            ApplyAttackTimePercentMod(BASE_ATTACK, oldVal, false);
            ApplyAttackTimePercentMod(OFF_ATTACK, oldVal, false);
            ApplyAttackTimePercentMod(BASE_ATTACK, newVal, true);
            ApplyAttackTimePercentMod(OFF_ATTACK, newVal, true);
            break;
        case CR_HASTE_RANGED:
            ApplyAttackTimePercentMod(RANGED_ATTACK, oldVal, false);
            ApplyAttackTimePercentMod(RANGED_ATTACK, newVal, true);
            break;
        case CR_HASTE_SPELL:
            //ApplyCastTimePercentMod(oldVal, false);
            //ApplyCastTimePercentMod(newVal, true);
            break;
        default:
            break;
    }
    UpdateRating(combatRating);
}

void Player::UpdateRating(CombatRating cr)
{
    int32 amount = m_baseRatingValue[cr];
    // Apply bonus from SPELL_AURA_MOD_RATING_FROM_STAT
    // stat used stored in miscValueB for this aura
    AuraEffectList const& modRatingFromStat = GetAuraEffectsByType(SPELL_AURA_MOD_RATING_FROM_STAT);
    for (AuraEffect const* aurEff : modRatingFromStat)
        if (aurEff->GetMiscValue() & (1 << cr))
            amount += int32(CalculatePct(GetStat(Stats(aurEff->GetMiscValueB())), aurEff->GetAmount()));

    if (amount < 0)
        amount = 0;
    SetUInt32Value(PLAYER_FIELD_COMBAT_RATING_1 + cr, uint32(amount));

    bool affectStats = CanModifyStats();

    switch (cr)
    {
        case CR_WEAPON_SKILL:                               // Implemented in Unit::RollMeleeOutcomeAgainst
        case CR_DEFENSE_SKILL:
            UpdateDefenseBonusesMod();
            break;
        case CR_DODGE:
            UpdateDodgePercentage();
            break;
        case CR_PARRY:
            UpdateParryPercentage();
            break;
        case CR_BLOCK:
            UpdateBlockPercentage();
            break;
        case CR_HIT_MELEE:
            UpdateMeleeHitChances();
            break;
        case CR_HIT_RANGED:
            UpdateRangedHitChances();
            break;
        case CR_HIT_SPELL:
            UpdateSpellHitChances();
            break;
        case CR_CRIT_MELEE:
            if (affectStats)
            {
                UpdateCritPercentage(BASE_ATTACK);
                UpdateCritPercentage(OFF_ATTACK);
            }
            break;
        case CR_CRIT_RANGED:
            if (affectStats)
                UpdateCritPercentage(RANGED_ATTACK);
            break;
        case CR_CRIT_SPELL:
            if (affectStats)
                UpdateAllSpellCritChances();
            break;
        case CR_HIT_TAKEN_MELEE:                            // Implemented in Unit::MeleeMissChanceCalc
        case CR_HIT_TAKEN_RANGED:
            break;
        case CR_HIT_TAKEN_SPELL:                            // Implemented in Unit::MagicSpellHitResult
            break;
        case CR_CRIT_TAKEN_MELEE:                           // Implemented in Unit::RollMeleeOutcomeAgainst (only for chance to crit)
        case CR_CRIT_TAKEN_RANGED:
            break;
        case CR_CRIT_TAKEN_SPELL:                           // Implemented in Unit::SpellCriticalBonus (only for chance to crit)
            break;
        case CR_HASTE_MELEE:                                // Implemented in Player::ApplyRatingMod
        case CR_HASTE_RANGED:
        case CR_HASTE_SPELL:
            break;
        case CR_WEAPON_SKILL_MAINHAND:                      // Implemented in Unit::RollMeleeOutcomeAgainst
        case CR_WEAPON_SKILL_OFFHAND:
        case CR_WEAPON_SKILL_RANGED:
            break;
        case CR_EXPERTISE:
            if (affectStats)
            {
                UpdateExpertise(BASE_ATTACK);
                UpdateExpertise(OFF_ATTACK);
            }
            break;
        case CR_ARMOR_PENETRATION:
            if (affectStats)
                UpdateArmorPenetration(amount);
            break;
    }
}

void Player::UpdateAllRatings()
{
    for (uint8 cr = 0; cr < MAX_COMBAT_RATING; ++cr)
        UpdateRating(CombatRating(cr));
}

您可以注意到我希望如何将新值结果限制为32000。 在计算百分比之前！

我尝试过使用 if（newVal> 32000） newVal = 32000;

我猜通常会做这个工作，但我遇到了错误 E0137表达式必须是可修改的左值

在线上newVal = 32000;

Answer 1

从const

中删除newVal限定词

float newVal = m_baseRatingValue[combatRating] * multiplier;

Answer 2

您将newVal声明为常量（float const newVal = ...），因此不允许您指定新值。

删除const应该对您有用，例如

float newVal = m_baseRatingValue[combatRating] * multiplier;

if (newVal > 32000)
    newVal = 32000;
...