6C++第六章教程.doc

第六章 运算符重载 #include iostream using namespace std; class Counter { private: int x; public: Counter (int a=0):x(a){} int getValue() { return x; } Counter operator-(); //friend Counter operator-(Counter c); }; Counter Counter::operator-() { return (-x); /* Counter c; c.x = -x; return c; */ } /* Counter operator-(Counter c) { return Counter(-c.x); } */ int main() { Counter c1(2), c2(2); coutc1.getValue()endl; c1 = -c2; coutc1.getValue()endl; coutc2.getValue()endl; } #include iostream #include cstring using namespace std; class STR { private: char* str; public: STR() { str = new char[1]; //strcpy(str, ); *str = 0; } STR(const char* s) { str = new char[strlen(s)+1]; strcpy(str, s); } ~STR() { if(str!=NULL) delete []str; } void show() { coutstrendl; } STR operator=(STR s) { if (strlen(str)==strlen(s.str)); else { delete str; str = new char[strlen(s.str)+1]; } strcpy(str, s.str); return *this; } STR operator+(STR s) { STR s1; s1.str = new char[strlen(str)+strlen(s.str)+1]; strcpy(s1.str, str); strcat(s1.str,s.str); return s1; } friend ostream operator(ostream os, STR s); friend istream operator(istream is, STR s); }; ostream operator(ostream os, STR s) { oss.str;//插入到输出流对象中 return os; } istream operator(istream is, STR s) { iss.str;//从输入流中提取操作 return is; } int main() { STR s1, s2(sd), s3(kj); s1.show(); s2.show(); (s2+s3).show(); s1 = s2; couts1; coutendl; cins3; couts3; } 运算符其实是一