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#include <iostream>

using namespace std;

class Stock{

protected:

Stock(){shares=0; share_val=0.0; Output();}

Stock(int n=0, double pr=3.5):_____(1)______{//初始化shares值为n

share_val=pr;

Output();

};

void ~Stock(){};

void Output(){cout << shares <<':' << share_val << endl;}

public:

//成员函数

private:

//成员变量

int shares;

double share_val;

};

void main(){ //构造三个Stock对象a，b，c

Stock a(1);

Stock b;

Stock c = Stock();

//其他代码省略，且代码无输出

}