class中缺省的4个函数的实现-优快云博客

本文介绍了C++类中的默认构造函数、拷贝构造函数、析构函数和赋值运算符重载的实现，通过实例展示了如何在C++中正确实现这些关键成员函数。

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class类中默认会实现4个函数，分别为默认构造函数，拷贝构造函数，析构函数和=运算符重载

#include <iostream> using namespace std; class myString { public: myString(const char *str=NULL); myString(const myString &other); ~myString(); myString & operator=(const myString &other); showString(); private: char *m_data; }; myString::~myString() { delete [] m_data; } myString::myString(const char *str) { if (str == NULL) { m_data = new char[1]; *m_data = '\0'; } else { int length = strlen(str)+1; m_data = new char[length]; while(*str != '\0') *m_data++ = *str++; *m_data = '\0'; } } myString::myString(const myString &other) { int length = strlen(other.m_data)+1; m_data = new char(length); strcpy(m_data,other.m_data); *m_data = '\0'; } myString & myString::operator=(const myString &other) { if (this == &other) { return *this; } delete []m_data; int length = strlen(other.m_data)+1; m_data = new char[length]; strcpy(m_data,other.m_data); return *this; } myString::showString() { cout<<this->m_data<<endl; } int main(int argc,char **argv) { myString str; char *p = "hello peter"; myString dest(p); dest.showString(); str = dest; str.showString(); return 0; }