C程序设计_对象分册(第3章)潘修改.pptVIP

第3章多态性;第3章多态性;3.1多态性的概念;3.2.1 运算符重载概述;3.2.1 运算符重载概述;3.2.1 运算符重载概述;3.2.2 双目运算符重载;C/C++程序设计教程--面向对象分册;【例3.2】定义复数类Complex，重载“+”运算符为它的成员函数 #include iostream class Complex { public: Complex (double r = 0, double i= 0) { real = r; image = i; } void print(); Complex operator+ ( const Complex c); private: double real, image; };;C/C++程序设计教程--面向对象分册;C/C++程序设计教程--面向对象分册;C/C++程序设计教程--面向对象分册;3.2.3 赋值运算符重载; void display( ) { coutbufferendl; } void set(char *string) { delete [ ] buffer; buffer= new char[strlen(string)+1]; strcpy(buffer, string); } CMessage operator=(const CMessage Message) { delete [ ] buffer; buffer= new char[strlen(Message.buffer)+1]; strcpy(buffer, Message.buffer); return *this; } private: char *buffer; };;void main( ) { CMessage c1; c1.set(initial c1 message); c1.display( ); CMessage c2; c2.set(initial c2 message); c2.display( ); c1=c2; c1.display( ); } 运行结果： initial c1 message initial c2 message initial c2 message;3.2.4 单目运算符重载 ;【例3.5】重载单目运算符“++”。 #includeiostream using namespace std; class Counter { public: Counter(int i=0){ v=i;} Counter operator ++(); //前置单目运算符 Counter operator ++(int); //后置单目运算符 void getValue(){coutvendl;} private: int v; }; Counter Counter::operator ++() //前置单目运算符 { ++v; return *this; } Counter Counter::operator ++(int) //后置单目运算符 { Counter t; t.v=v++; return t; };int main() { Counter c1(5),c2(5),c3,c4; int i; c3 = c1++; //后置单目运算符 coutc3.v=; c3.getValue(); c4 = ++c2; //前置单目运算符 coutc4.v=; c4.getValue(); return 0; } 运行结果： c3.v=5 c4.v=6;3.2.5 下标运算符重载;{ len=m; str=new char[len]; memset(str,0,len); } MyCharArray(char *s) { str=new char[strlen(s)+1]; strcpy(str,s); len=strlen(s); } ~MyCharArray() { delete []str; } char operator[](int n) { static char ch=0; if(nlen-1) { cou