c++ - 为什么 int 变量在这个函数中不起作用？

Question

我创建了一个函数来创建 cows 变量，然后我创建了另一个函数来屠杀它们。这两个函数是类中的方法。当我使用 create cow 函数时，它起作用了，我得到了 cows 的值。但是，当我访问屠夫函数时，奶牛的值为零。

这就像有两个不同的变量；我不认为函数如果是 void 函数就可以有局部变量。

我该如何解决这个问题？

#include <string>
using namespace std;

class Cheif
{
    int points;
    string name;

protected:
    int NoodleS;
    int RosemaryS;
    int ParcleyS;
    int PepperS;
    int Field;
    int Water;

public:
    int star; 
    int foodPrep; 
    int ingrPrep;     
    int endOfPrep;
    int money;
    int ingr1;
    int ingr2;
    int ingr3;
    int Noodle;
    int Rosemary;
    int Parcley;
    int Pepper;
    int chickMeat;
    int beef;
    int chickens;
    int cows;

// constructor 
    Cheif()
    {
        money = 1000;
        points = 0;
        star = 10;    
        endOfPrep = 0; 
        ingr1 = 0;
        ingr2 = 0;
        ingr3 = 0;
        Noodle = 0;
        Rosemary = 0;
        Parcley = 0;
        Pepper= 0 ;
        cows = 0;
        chickens = 0;
        beef = 0;
        chickMeat = 0;
    }

// method

//////////////////////////////////////////////////
//                                              //
//            ask user for their name           //
//                                              //
//////////////////////////////////////////////////
    void FindName()
    {

        cout << "what is your name? " << endl;;
        cin >> name;
        cout << endl << " Welcome " << name
         << " let us begin... " <<endl;   


    }

//////////////////////////////////////////////////
//                     END                      //
//////////////////////////////////////////////////

//////////////////////////////////////////////////
//                                              //
//         Buy animal live stock                //
//                                              //
//////////////////////////////////////////////////
    void Buy_Cow()
    {
        if(money > 199)
        {
        money -= 200;
        cows += 1;
        cout <<" you now have " << cows << " cows" << endl;
        }
    }

    void Buy_Chick()
    {
        if(money > 99)
        {
        money -= 200;
        chickens += 1;
        } 
    }

//////////////////////////////////////////////////
//                     END                      //
//////////////////////////////////////////////////


//////////////////////////////////////////////////
//                                              //
//         if user goes to open store           //
//                                              //
//////////////////////////////////////////////////

    void GOTO_Store()
    {
        // while food is not prepared yet
        while(endOfPrep == 0){
        PREPAREMEAL:
        // show menu
        cout << "<1> Make Food \n"
             << "<2> Collect Ingridents \n"        
             << "<3> Butcher Animal \n"
             << "<4> Go Back... \n" << endl;


        // create variable to hold choice
        string OS_Choice;

        cin >> OS_Choice;   

        /////////// if user decides to "make food" /////////////
        if (OS_Choice == "1")
        {
            if(foodPrep == 1)
            {
            cout << "you've already prepared the meal..." << endl;         
            }else{          
            if(ingr1 <= 0 ||ingr2 <= 0 || ingr3 <= 0)
            {
                goto PREPAREMEAL;
            }else{          
                cout << "your using" << ingr1 << " " << ingr2<< " " << ingr3 << endl;
            } // end of ingredient check

            cout << " and how shall this mean be prepared? " << endl;

            int prepMethod;

            cout << "<1> Baked \n "
                 << "<2> boiled \n "
                 << "<3> Fried \n "
                 << "<4> mixed \n ";

            cin >> prepMethod;

            cout << " And what kind of sides would you like to add? " << endl;

            int sideChoice;

            cout << "<1> bread Roll \n " 
                 << "<2> Rice \n "
                 << "<3> Beans \n" << endl;

            cin >> sideChoice;

            foodPrep = 1;
            }// end of food choice 

            //begin food compare. 
            /////////// if user decides to get ingrediants /////////////
        }else if(OS_Choice == "2"){
            if (ingrPrep == 1){
            cout << " you have already collected the ingredients " << endl;  

            }else{     
            cout << "what 3 ingridents will you use? " << endl;
            cin >> ingr1;
            cin >> ingr2;
            cin >> ingr3;
            }// end of ingrident prep
            /////////// if user decides to get ingrediants /////////////
        }else if(OS_Choice == "3")
        {
            cout << " you have " << cows << " cows \n "
             << " you have " << chickens << " Chickens \n ";

            cout << "what would you like to butcher? " << endl;
            cout << "<1> Cows    : " << cows << endl;
            cout << "<2> Chicken : " << chickens << endl;
            int B_Choice;

            cin >> B_Choice;

            if(B_Choice == 1){
            if(cows == 0){
                cout << " sorry you dont have any cows " << endl;
            }else{
                cows = cows - 1;
                beef = beef + 5;
                cout << " you now have " << beef << "peices of cow meat" << endl;
                ingrPrep = 1;
            }//end of cow check
            }else if(B_Choice == 2){
            if(chickens == 0){
                cout << " sorry you dont have any chickens " << endl;
            }else{
                chickens = chickens - 1;
                chickMeat = chickMeat + 2;
                cout << " you now have " << chickMeat << "peices of Chicken meat" << endl;
                ingrPrep = 1;
            } // end chicken Check
            }else {
            cout << "invalid Choice" << endl;
            }// end of b choice
        }else if(OS_Choice == "4") {
            endOfPrep = 1;      
            foodPrep = 0;
            ingrPrep = 0;
            ingr1 = 0;
            ingr2 = 0;
            ingr3 = 0;
        }// end of ingr prep. 
        }//end of while loop  
    }
//////////////////////////////////////////////////
//                     END                      //
//////////////////////////////////////////////////
};

Answer 1

您的类的构造没有明显的错误会导致您所描述的问题。 (要点 unwind 说明将方法实现直接放在类声明中通常不是一个好主意是正确的，但这不是问题的原因。)

事实上，如果我在您发布的代码末尾添加一个简单的 main():

int main() {

   Cheif c;

   c.Buy_Cow();
   c.GOTO_Store();
}

并编译并运行它，它给出了预期的结果(cows=1 的值)。

所以，这告诉您问题不在于此类，而在于您如何从程序的其余部分调用它。

要追踪到这一点，可以使用常用的调试技术。例如:

• 尝试确定导致问题的特定事件序列
• 使用调试器和/或打印语句找出问题所在