C++兩種字符串傳參構造函數

第一種：

#include"iostream"
#include"string"
using namespace std;

class Motor{
protected:
    int n;
    int tire;
    double motor;
    char *str1;    //基類為指針
    char *str2;
public:
    virtual void Display()=0;
};

class Car:public Motor{
public:
    Car(char *Str1,char *Str2,int N,int Tire,double Motor){
        str1 = new char[strlen(Str1)+1];    //要先獲得字符串大小
        str2 = new char[strlen(Str2)+1];
        strcpy(str1,Str1);
        strcpy(str2,Str2);
        n = N;
        tire = Tire;

        motor = Motor;
    }
    ~Car(){
        delete[] str1;    //最后要刪除內存
        delete[] str2;
    };
    virtual void Display(){
        cout<<"the car"<<"可載人數:"<<n<<"、輪胎數:"<<tire<<"、馬力數:"<<motor<<endl;
        cout<<"產於"<<str1<<"車的主人為："<<str2<<endl;
    }
};

第一種相對而言可以節省內存，不怕傳入的字符串過長，但要記得刪除指針釋放內存

第二種：

#include"iostream"
using namespace std;
#define pi 3.14159

class Motor{
protected:
    int man,wheel,mata;
    char produce[20];    //基類為數組
    char owner[20];
public:
    Motor(int m,int w,int ma,char* pro,char* own){
        man=m; wheel=w; mata=ma;
        strcpy(produce,pro);    //不必獲得字符串大小，因開始已指定
        strcpy(owner,own);
    }
    //無需虛構函數去刪除指針，不會泄露內存
    virtual void Dispaly(){
        cout<<"the motor"<<"可載人數:"<<man<<"、輪胎數:"<<wheel<<"、馬力數:"<<mata<<endl;
        cout<<"產於"<<produce<<"車的主人為："<<owner<<endl;
    }
};

class Car:public Motor{
public:
    Car(int m,int w,int ma,char* pro,char* own):Motor(m, w, ma, pro, own){}
    void Dispaly(){
        cout<<"the car"<<"可載人數:"<<man<<"、輪胎數:"<<wheel<<"、馬力數:"<<mata<<endl;
        cout<<"產於"<<produce<<"車的主人為："<<owner<<endl;
    }
};

第二種相對而言更簡便，但往往浪費內存，不確定傳入的字符串參數大小。