{cout<<this->stockcode<<this->quan<<this->price<<endl;}

void main()
{
stock a("hgj",2,6);
a.print();
}

我加了一个头文件、两个分号和一对括号，程序就正确了，你比较一下吧。
#include <string.h>
#include <iostream>
class stock
{
char stockcode[20];
int quan;
float price;
public:
stock(char na[20],int q=1000,float p=8.98)
{strcpy(stockcode,na);
quan=q;
price=p;
}
void print()
{
std::cout<<this->stockcode<<this->quan<<this->price<<std::endl;
}
};
void main()
{
stock a("hgj",2,6) ;
a.print() ;
}