php整站开发 企业网站教程,朋友圈推广平台,wordpress 表格样式,南康区城乡规划建设局网站实现了 MyString 类#xff0c;同时实现了运算符重载#xff0c;重载的运算符包括 、、、!、、、[] 等。 如果一个类重载了某个运算符#xff0c;那么对这个类的对象进行操作的时候便会使用类重载的运算符。比如下边代码 MyString 类中重载了 、…实现了 MyString 类同时实现了运算符重载重载的运算符包括 、、、!、、、[] 等。 如果一个类重载了某个运算符那么对这个类的对象进行操作的时候便会使用类重载的运算符。比如下边代码 MyString 类中重载了 、、、!、、 运算符那么使用这些运算符操作对象的时候便会使用对象重载之后的运算符。 (1) 、、、!
① 4 个运算符重载可以声明为友元函数也可以声明为类的成员函数
② 声明友元函数时形参是两个声明为成员函数时形参是一个
③ 对象 O1 和 O2 进行比较成员函数是 O1.operator (O1)友元函数是 operator (O1, O2)
④ 声明为成员函数时默认会带一个 this 指针*this 是左操作数
(2) 流操作符需要声明为友元函数不能声明为成员函数
(3) 不能创建新的运算符只能重载已有的运算符 如下代码、、、!、、 均声明为友元函数。
#include stdlib.h
#include stdio.h
#include string.h
#include iostream
#include stringclass MyString {
public:MyString(); // 默认构造函数MyString(int n, char c); // 普通构造函数MyString(const char *str); // 普通构造函数MyString(const MyString str); // 拷贝构造函数MyString operator (char *str); // 重载 使用字符串赋值MyString operator (const MyString s); // 重载 使用对象赋值~MyString(); // 析构函数char operator[] (int i); // 重载 [], 实现数组操作const char operator[] (int i) const; // 重载 []事项数组操作对象为常量MyString operator (const MyString str); // 重载 与对象相加MyString operator (const char *str); // 重载 与字符串相加friend std::ostream operator (std::ostream out, MyString str); // 重载 实现输出流friend std::istream operator (std::istream in, MyString str); // 重载 实现输入流friend bool operator (const MyString left, const MyString right); // 重载 friend bool operator (const MyString left, const MyString right); // 重载 friend bool operator (const MyString left, const MyString right); // 重载 friend bool operator ! (const MyString left, const MyString right); // 重载 !char *GetData() const;// 对象被声明为 const那么这个对象调用的函数也需要是 const 类型int Size() const;private:int size;char *data nullptr;
};MyString::MyString() {// 默认构造函数只包括一个字符 \0printf(MyString()\n);data new char[1];*data \0;size 0;
}MyString::MyString(int n, char c) {printf(MyString(int n, char c), n %d, c %c\n, n, c);data new char[n 1];for (int i 0; i n; i) {*(data i) c;}*(data n) \0;size n;
}MyString::MyString(const char *str) {printf(MyString(const char *str), str %s\n, str);if (str nullptr) {data new char[1];*data \0;size 0;} else {data new char[strlen(str) 1];strcpy(data, str);size strlen(str);}
}MyString::MyString(const MyString str) {printf(MyString(const MyString str), str %s\n, str.GetData());data new char[str.size 1];strcpy(data, str.data);size str.size;
}MyString MyString::operator (char *str) {printf(operator , MyString char *, str %s\n, str);if (data ! nullptr) {delete []data;}data new char[strlen(str) 1];strcpy(data, str);return *this;
}MyStringMyString::operator (const MyString str) {printf(operator , MyString MyString, str %s\n, str.GetData());if (this str) {return *this;}if (data ! nullptr) {delete []data;}data new char[str.size 1];strcpy(data, str.data);return *this;
}MyString::~MyString() {if (data ! nullptr) {delete []data;data nullptr;size 0;}
}char MyString::operator [](int i) {return data[i];
}const char MyString::operator[] (int i) const {printf(operator [], const\n);return data[i];
}MyString MyString::operator (const MyString s) {printf(operator MyString, str %s\n, s.GetData());int length size s.size 1;char *tmp data;data new char[length];size length - 1;strcpy(data, tmp);strcat(data, s.data);delete []tmp;return *this;
}MyString MyString::operator (const char *str) {printf(operator char *, str %s\n, str);if (str nullptr) {return *this;}int length size strlen(str) 1;char *tmp data;data new char[length];size length - 1;strcpy(data, tmp);strcat(data, str);delete []tmp;return *this;
}int MyString::Size() const {return size;
}char* MyString::GetData() const {return data;
}std::ostream operator (std::ostream out, MyString str) {for (int i 0; i str.Size(); i) {out str[i] ;}return out;
}std::istream operator (std::istream in, MyString str) {char p[50];in.getline(p, 50);str p;return in;
}bool operator (const MyString left, const MyString right) {int i 0;while (left[i] ! \0 right[i] ! \0 left[i] right[i]) {i;}if (left[i] right[i]) {return true;}return false;
}bool operator (const MyString left, const MyString right) {int i 0;while (left[i] ! \0 right[i] ! \0 left[i] right[i]) {i;}if (left[i] right[i]) {return true;}return false;
}bool operator (const MyString left, const MyString right) {if (left.Size() ! right.Size()) {return false;}int i 0;while (left[i] ! \0 right[i] ! \0) {if (left[i] ! right[i]) {return false;}i;}return true;
}bool operator ! (const MyString left, const MyString right) {if (left.Size() ! right.Size()) {return true;}int i 0;while (left[i] ! \0 right[i] ! \0) {if (left[i] ! right[i]) {return true;}i;}return false;
}int main() {printf(构造 --------------------------------\n);MyString s1(3, a); // 默认构造函数MyString s2(s1); // 拷贝构造函数MyString s3(abcdefghijklmn); // 通过 char * 来构造函数MyString s4; // 空的字符串printf(\noperator --------------------------------\n);std::cout s1: s1 std::endl; // 输出字符串使用重载的运算符 std::cout s2: s2 std::endl;std::cout s3: s3 std::endl;std::cout s4: s4 std::endl;printf(\noperator --------------------------------\n);s4 s3; // 字符串赋值使用字符串对象赋值std::cout s4: s4 std::endl;s4 abcd; // 使用 char * 赋值std::cout s4: s4 std::endl;std::cout s4[2] s4[2] std::endl;printf(\noperator --------------------------------\n);s4 mmmm;std::cout s4: s4 std::endl;s4 s2;std::cout s4: s4 std::endl;printf(\noperator --------------------------------\n);std::cin s2;std::cout s2: s2 std::endl;printf(\n, , , ! --------------------------------\n);MyString t1 1234;MyString t2 1234;MyString t3 12345;MyString t4 12335;std::cout t1 t2 ? (t1 t2) std::endl;std::cout t1 t3 ? (t1 t3) std::endl;std::cout t1 t4 ? (t1 t4) std::endl;std::cout t1 ! t4 ? (t1 ! t4) std::endl;return 0;
}如下代码、、、! 声明为成员函数当成员函数和友元函数同时存在时优先选用成员函数。
#include stdlib.h
#include stdio.h
#include string.h
#include iostream
#include stringclass MyString {
public:MyString(); // 默认构造函数MyString(int n, char c); // 普通构造函数MyString(const char *str); // 普通构造函数MyString(const MyString str); // 拷贝构造函数MyString operator (char *str); // 重载 使用字符串赋值MyString operator (const MyString s); // 重载 使用对象赋值~MyString(); // 析构函数char operator[] (int i); // 重载 [], 实现数组操作const char operator[] (int i) const; // 重载 []事项数组操作对象为常量MyString operator (const MyString str); // 重载 与对象相加MyString operator (const char *str); // 重载 与字符串相加friend std::ostream operator (std::ostream out, MyString str); // 重载 实现输出流friend std::istream operator (std::istream in, MyString str); // 重载 实现输入流friend bool operator (const MyString left, const MyString right); // 重载 friend bool operator (const MyString left, const MyString right); // 重载 friend bool operator (const MyString left, const MyString right); // 重载 friend bool operator ! (const MyString left, const MyString right); // 重载 !bool operator (const MyString str); // 重载 bool operator (const MyString str); // 重载 bool operator (const MyString str); // 重载 bool operator ! (const MyString str); // 重载 !char *GetData() const;// 对象被声明为 const那么这个对象调用的函数也需要是 const 类型int Size() const;private:int size;char *data nullptr;
};MyString::MyString() {// 默认构造函数只包括一个字符 \0printf(MyString()\n);data new char[1];*data \0;size 0;
}MyString::MyString(int n, char c) {printf(MyString(int n, char c), n %d, c %c\n, n, c);data new char[n 1];for (int i 0; i n; i) {*(data i) c;}*(data n) \0;size n;
}MyString::MyString(const char *str) {printf(MyString(const char *str), str %s\n, str);if (str nullptr) {data new char[1];*data \0;size 0;} else {data new char[strlen(str) 1];strcpy(data, str);size strlen(str);}
}MyString::MyString(const MyString str) {printf(MyString(const MyString str), str %s\n, str.GetData());data new char[str.size 1];strcpy(data, str.data);size str.size;
}MyString MyString::operator (char *str) {printf(operator , MyString char *, str %s\n, str);if (data ! nullptr) {delete []data;}data new char[strlen(str) 1];strcpy(data, str);return *this;
}MyStringMyString::operator (const MyString str) {printf(operator , MyString MyString, str %s\n, str.GetData());if (this str) {return *this;}if (data ! nullptr) {delete []data;}data new char[str.size 1];strcpy(data, str.data);return *this;
}MyString::~MyString() {if (data ! nullptr) {delete []data;data nullptr;size 0;}
}char MyString::operator [](int i) {return data[i];
}const char MyString::operator[] (int i) const {return data[i];
}MyString MyString::operator (const MyString s) {printf(operator MyString, str %s\n, s.GetData());int length size s.size 1;char *tmp data;data new char[length];size length - 1;strcpy(data, tmp);strcat(data, s.data);delete []tmp;return *this;
}MyString MyString::operator (const char *str) {printf(operator char *, str %s\n, str);if (str nullptr) {return *this;}int length size strlen(str) 1;char *tmp data;data new char[length];size length - 1;strcpy(data, tmp);strcat(data, str);delete []tmp;return *this;
}int MyString::Size() const {return size;
}char* MyString::GetData() const {return data;
}std::ostream operator (std::ostream out, MyString str) {for (int i 0; i str.Size(); i) {out str[i] ;}return out;
}std::istream operator (std::istream in, MyString str) {char p[50];in.getline(p, 50);str p;return in;
}bool operator (const MyString left, const MyString right) {int i 0;while (left[i] ! \0 right[i] ! \0 left[i] right[i]) {i;}if (left[i] right[i]) {return true;}return false;
}bool operator (const MyString left, const MyString right) {int i 0;while (left[i] ! \0 right[i] ! \0 left[i] right[i]) {i;}if (left[i] right[i]) {return true;}return false;
}bool operator (const MyString left, const MyString right) {if (left.Size() ! right.Size()) {return false;}int i 0;while (left[i] ! \0 right[i] ! \0) {if (left[i] ! right[i]) {return false;}i;}return true;
}bool operator ! (const MyString left, const MyString right) {if (left.Size() ! right.Size()) {return true;}int i 0;while (left[i] ! \0 right[i] ! \0) {if (left[i] ! right[i]) {return true;}i;}return false;
}//
bool MyString::operator (const MyString str) {int i 0;while (data[i] ! \0 str[i] ! \0 data[i] str[i]) {i;}if (data[i] str[i]) {return true;}return false;
}bool MyString::operator (const MyString str) {int i 0;while (data[i] ! \0 str[i] ! \0 data[i] str[i]) {i;}if (data[i] str[i]) {return true;}return false;
}bool MyString::operator (const MyString str) {if (size ! str.Size()) {return false;}int i 0;while (data[i] ! \0 str[i] ! \0) {if (data[i] ! str[i]) {return false;}i;}return true;
}bool MyString::operator ! (const MyString str) {if (size ! str.Size()) {return true;}int i 0;while (data[i] ! \0 str[i] ! \0) {if (data[i] ! str[i]) {return true;}i;}return false;
}int main() {printf(构造 --------------------------------\n);MyString s1(3, a); // 默认构造函数MyString s2(s1); // 拷贝构造函数MyString s3(abcdefghijklmn); // 通过 char * 来构造函数MyString s4; // 空的字符串printf(\noperator --------------------------------\n);std::cout s1: s1 std::endl; // 输出字符串使用重载的运算符 std::cout s2: s2 std::endl;std::cout s3: s3 std::endl;std::cout s4: s4 std::endl;printf(\noperator --------------------------------\n);s4 s3; // 字符串赋值使用字符串对象赋值std::cout s4: s4 std::endl;s4 abcd; // 使用 char * 赋值std::cout s4: s4 std::endl;std::cout s4[2] s4[2] std::endl;printf(\noperator --------------------------------\n);s4 mmmm;std::cout s4: s4 std::endl;s4 s2;std::cout s4: s4 std::endl;printf(\noperator --------------------------------\n);std::cin s2;std::cout s2: s2 std::endl;printf(\n, , , ! --------------------------------\n);MyString t1 1234;MyString t2 1234;MyString t3 12345;MyString t4 12335;std::cout t1 t2 ? (t1 t2) std::endl;std::cout t1 t3 ? (t1 t3) std::endl;std::cout t1 t4 ? (t1 t4) std::endl;std::cout t1 ! t4 ? (t1 ! t4) std::endl;return 0;
}
