C++ "Invalid use of 'this' in non-member function",

Question

以下是我的角色 class 及其子 class 的 .cpp 版本。我正在尝试让 attack() 函数发挥作用。我做了一些更改，当前错误处理 adjustHP() 函数中的 "invalid use of ‘this’ in non-member function"。在我的主要 class 中，我正在实例化玩家扮演的 Warrior 对象和 Goblin 作为无法控制的敌人。

character.cpp

character::character(double hp ,double atk, double defense, double speed){
    this->hp= hp;
    this->atk = atk;
    this->defense = defense;
    this->speed = speed;
}

double character::getHP() {
    return this->hp;
}

double character::getATK() {
    return this->atk;
}

double character::getDEFENSE() {
    return this->defense;
}

double character::getSPEED() {
    return this->speed;
}

warrior.cpp

Warrior::Warrior():character(hp,atk,defense,speed) { // Constructor
    this->hp= 50;
    this->atk = 50;
    this->defense = 50;
    this->speed = 50;
}

void Warrior::adjustHP(double adjustBy) {
    this->hp = this->hp - adjustBy;
}

void Warrior::attack(character* enemy) {
    enemy->adjustHP(10);
}

goblin.cpp

Goblin::Goblin() : character(hp,atk,defense,speed) { // Constructor
    this->hp= 60;
    this->atk = 40;
    this->defense = 40;
    this->speed = 40;
}

void adjustHP(double adjustBy) {
    this->hp = this->hp-adjustBy;
}

void Goblin::attack(character* playerChoice ) {
    playerChoice->adjustHP(10);
}

Answer 1

比较你的

void adjustHP(double adjustBy) {

与您的预期一致：

void Goblin::adjustHP(double adjustBy) {

C++ 不会阻止您在 goblin.cpp 中定义不相关的自由 adjustHP 函数并在该文件中保留 Goblin::adjustHP 未定义。

Answer 2

在 goblin.cpp 中，您将 adjustHP 定义为非成员函数。应该是：

void Goblin::adjustHP(double adjustBy) {
this->hp = this->hp-adjustBy;
}

C++ "Invalid use of 'this' in non-member function",

C++ "Invalid use of 'this' in non-member function",

c++

inheritance

pointers

class

non-member-functions