class S{ //... friend int operator[](S, int); int operator!(int); //... };
时间: 2024-03-31 18:38:47 浏览: 24
这段代码定义了一个名为`S`的类,其中包含了一个友元函数`operator[]`和一个成员函数`operator!`。其中,`operator[]`是一个全局函数,它的第一个参数是一个`S`类的对象,第二个参数是一个`int`类型的整数,返回值是一个`int`类型的整数。这里使用了`friend`关键字将全局函数`operator[]`声明为`S`类的友元函数,使得`operator[]`函数可以访问`S`类的私有成员。
`operator!`是一个成员函数,它的参数是一个`int`类型的整数,返回值是一个`int`类型的整数。`operator!`是一个一元运算符,因此只需要一个参数,但是它的参数类型与返回值类型都是`int`类型,这在语法上是合法的,但是在实际应用中可能会引起歧义,因此应该尽量避免这种写法。
总的来说,这段代码的语法是正确的,但是需要注意`operator!`函数的参数和返回值类型可能会引起歧义。
相关问题
请完成Complex类的定义,使得下面的主函数能正常运行。 int main( ) { Complex c1(1,2); cout<<"c1="<<c1; //operator<<(cout,c1); Complex c2(2); // default argument is i=0 cout<<"c2="<<c2<<endl; Complex c3(c1); //invoke the copy constructor cout<<"c3="<<c3; c1=c1+c2+c3; // c1=(c1.operator+(c2)).operator+(c3); cout<<"c1=c1+c2+c3="<<c1; c2=-c3; // c2=c3.operator-(); cout<<"c2=-c3="<<c2; c3=c2-c1; // c3=c2.operator-(c1); cout<<"c3=c2-c1="<< c3; Complex r2=2+c2; // calls operator+ (2, c2) cout<<"r2=2+c2="<<r2; Complex c4; cin>>c4; cout<<"c4="<<c4; cout<<"the module of c4 is: "<<c4.GetMagnitude()<<endl;//计算复数的模 return 0; }
```c++
#include <iostream>
#include <cmath>
using namespace std;
class Complex {
private:
double real; // 实部
double imag; // 虚部
public:
// 构造函数
Complex(double r = 0, double i = 0) : real(r), imag(i) {}
// 拷贝构造函数
Complex(const Complex& c) {
real = c.real;
imag = c.imag;
}
// 重载运算符 +
Complex operator+(const Complex& c) const {
return Complex(real + c.real, imag + c.imag);
}
// 重载运算符 -
Complex operator-(const Complex& c) const {
return Complex(real - c.real, imag - c.imag);
}
// 重载运算符 - (负号)
Complex operator-() const {
return Complex(-real, -imag);
}
// 重载运算符 + (用于实数与复数相加)
friend Complex operator+(double r, const Complex& c) {
return Complex(r + c.real, c.imag);
}
// 重载运算符 << (输出运算符)
friend ostream& operator<<(ostream& os, const Complex& c) {
os << c.real << "+" << c.imag << "i";
return os;
}
// 重载运算符 >> (输入运算符)
friend istream& operator>>(istream& is, Complex& c) {
cout << "请输入实部和虚部(以空格分隔):";
is >> c.real >> c.imag;
return is;
}
// 计算复数的模
double GetMagnitude() const {
return sqrt(real * real + imag * imag);
}
};
int main() {
Complex c1(1, 2);
cout << "c1=" << c1 << endl;
Complex c2(2);
cout << "c2=" << c2 << endl;
Complex c3(c1);
cout << "c3=" << c3 << endl;
c1 = c1 + c2 + c3;
cout << "c1=c1+c2+c3=" << c1 << endl;
c2 = -c3;
cout << "c2=-c3=" << c2 << endl;
c3 = c2 - c1;
cout << "c3=c2-c1=" << c3 << endl;
Complex r2 = 2 + c2;
cout << "r2=2+c2=" << r2 << endl;
Complex c4;
cin >> c4;
cout << "c4=" << c4;
cout << "the module of c4 is: " << c4.GetMagnitude() << endl;
return 0;
}
```
用c++构造一个日期类Date,要求重载:流提取和流插入运算符,重载前置和后置自增运算符(必要时递增年月)。类定义如下: // Date class definition. #ifndef DATE_H #define DATE_H #include <iostream> using std::ostream; class Date { friend ostream &operator<<( ostream &, const Date & ); public: Date( int m = 1, int d = 1, int y = 1900 ); // default constructor void setDate( int, int, int ); // set month, day, year Date &operator++(); // prefix increment operator Date operator++( int ); // postfix increment operator const Date &operator+=( int ); // add days, modify object bool leapYear( int ) const; // is date in a leap year? bool endOfMonth( int ) const; // is date at the end of month? private: int month; int day; int year; static const int days[]; // array of days per month void helpIncrement(); // utility function for incrementing date }; // end class Date #endif
以下是基于你提供的类定义的C++代码:
```
#include <iostream>
#include "Date.h"
using std::ostream;
// Define static member days.
const int Date::days[] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
// Constructor: initialize month, day, year.
Date::Date(int m, int d, int y)
{
setDate(m, d, y);
}
// Set the date.
void Date::setDate(int m, int d, int y)
{
month = (m >= 1 && m <= 12) ? m : 1;
year = (y >= 1900 && y <= 2100) ? y : 1900;
// Test for a leap year.
if (month == 2 && leapYear(year))
day = (d >= 1 && d <= 29) ? d : 1;
else
day = (d >= 1 && d <= days[month]) ? d : 1;
}
// Prefix increment operator.
Date& Date::operator++()
{
helpIncrement();
return *this;
}
// Postfix increment operator.
Date Date::operator++(int)
{
Date temp = *this;
helpIncrement();
return temp;
}
// Add days to the date.
const Date& Date::operator+=(int additionalDays)
{
for (int i = 0; i < additionalDays; i++)
helpIncrement();
return *this;
}
// Determine if the year is a leap year.
bool Date::leapYear(int testYear) const
{
if (testYear % 400 == 0 || (testYear % 100 != 0 && testYear % 4 == 0))
return true;
else
return false;
}
// Determine if the date is at the end of the month.
bool Date::endOfMonth(int testDay) const
{
if (month == 2 && leapYear(year))
return testDay == 29;
else
return testDay == days[month];
}
// Utility function to increment the date.
void Date::helpIncrement()
{
if (!endOfMonth(day))
day++;
else
{
if (month < 12)
month++;
else
{
month = 1;
year++;
}
day = 1;
}
}
// Overloaded stream insertion operator.
ostream& operator<<(ostream& output, const Date& d)
{
static char* monthName[13] = { "", "January", "February",
"March", "April", "May", "June", "July", "August", "September",
"October", "November", "December" };
output << monthName[d.month] << ' ' << d.day << ", " << d.year;
return output;
}
```
可以在代码中添加其他函数和运算符的实现以满足你的需求。
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