C++ 复制构造函数和赋值操作符

复制构造函数的适用情况

1.对象的定义形式 - 复制初始化

2.形参与返回值

3.初始化容器

#include <iostream>

#include <string>

#include <vector>

using namespace std;

class Sales_item

{

public:

Sales_item():units_sold(0),revenue(0.0)

{

cout << "默认构造函数被调用" << endl;

}

Sales_item(const std::string &book):isbn(book),units_sold(0),revenue(0.0)

{

cout << "构造函数Sales_item(const std::string &book)被调用" << endl;

}

//复制构造函数

Sales_item(const Sales_item &orig)

:isbn(orig.isbn),

units_sold(orig.units_sold),

revenue(orig.revenue)

{

cout << "复制构造函数被调用" << endl;

}

//赋值操作符

Sales_item& operator=(const Sales_item &rhs)

{

cout << "赋值操作符被调用" << endl;

isbn = rhs.isbn;

units_sold = rhs.units_sold;

revenue = rhs.revenue;

return *this;

}

private:

std::string isbn;

unsigned units_sold;

double revenue;

};

Sales_item foo(Sales_item item)

{

cout << endl;

Sales_item temp;

temp = item;

return temp;

}

int main()

{

Sales_item a;

Sales_item b("0-201-78345-X");

Sales_item c(b);

a = b;

Sales_item item = string("9-999-99999-9");

cout << "====================="<<endl;

Sales_item ret;

ret = foo(b);

cout << endl<<"vetor=============" << endl;

vector<Sales_item> svec(5);

cout << endl<<"数组=============" << endl;

Sales_item primer[] = {

string("9-999-99999-1"),

string("9-999-99999-2"),

string("9-999-99999-93"),

Sales_item()

};

return 0;

}