本文實(shí)例為大家分享了c++編寫String類的具體代碼,供大家參考,具體內(nèi)容如下
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class String { public : String( const char * = nullptr); //普通構(gòu)造函數(shù) String( const String& other); //拷貝構(gòu)造函數(shù) ~String( void ); //析構(gòu)函數(shù) String& operator = ( const String& other); //賦值函數(shù) private : char * m_data; }; //普通構(gòu)造函數(shù) String::String( const char * str) { if (str == nullptr){ m_data = new char [1]; //對(duì)空字符自動(dòng)申請(qǐng)存放結(jié)束標(biāo)志'\0'的空 *m_data = '\0' ; } else { m_data = new char [ strlen (str) + 1]; //+1是為了多余一個(gè)字符存放'\0' strcpy (m_data, str); } } //拷貝構(gòu)造函數(shù) String::String( const String& other) { if (other == nullptr){ m_data = nullptr; } else { //注意下面括號(hào)里面都是other.m_data m_data = new char [ strlen (other.m_data) + 1]; strcpy (m_data, other.m_data); } } //析構(gòu)函數(shù) String::~String( void ) { if (m_data != nullptr){ delete [] m_data; m_data = nullptr; } } //賦值運(yùn)算符 String& String::operator=( const String& other) { //判斷是否是給自己賦值 if ( this != other){ delete [] m_data; //先釋放掉原來的內(nèi)存 if (other == nullptr){ m_data = nullptr; } else { m_data = new char [ strlen (other.m_data) + 1]; strcpy (m_data, other.m_data); } } return * this ; } |
另外兩個(gè)是重載+號(hào)和=號(hào)
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String& operator + (String& other) { char * tmp = m_data; m_data = new char [ strlen (m_data) + strlen (other.m_data) + 1]; strcpy (m_data, tmp); //復(fù)制第一個(gè)字符串 strcpy (m_data, other.m_data); //復(fù)制第二個(gè)字符串 delete [] tmp; //記得刪除這個(gè)內(nèi)存 return * this ; } String& operator = (String& other) { if ( this = other){ return * this ; } if (m_data != nullptr){ delete [] m_data; //先釋放之前的內(nèi)存 } m_data = new char [ strlen (other.m_data) + 1]; strcpy (m_data, other.m_data); return * this ; } |
以上所述是小編給大家介紹的c++編寫String類詳解整合,希望對(duì)大家有所幫助,如果大家有任何疑問請(qǐng)給我留言,小編會(huì)及時(shí)回復(fù)大家的。在此也非常感謝大家對(duì)服務(wù)器之家網(wǎng)站的支持!