[問題] overload operator ==

看板C_and_CPP (C/C++)作者vic1225 (/* I'm not worth */)時間15年前 (2010/08/18 23:55)推噓1(1推 0噓 29→)

留言30則, 5人參與討論串1/1

#include <iostream> #include <stdlib.h> using namespace std; class String { private: char *str; int length; public: //construct String(int ); String(char *); //copy construct String(const String & ); //destuct ~String(); void reserve(); int lengthof(); String operator=(const String & ); char operator[](int ); String operator+(const String & ); //bool operator==(const String ); }; int main(){ String x("Iwillbe."); String y(20); String z(20); cout << "Length of x is " << x.lengthof() << endl; y = x; cout << "Index 5 of y is " << y[5] << endl; // cout << "Is x = y ? " << (x==y) << endl; z = x + y; cout << "Length of z is " << z.lengthof() << endl; cout << "Index 11 of z is " << z[11] << endl; system("pause"); return 0; } String::String(int n){ length = n; if(length < 0){ cout << "Length < 0 is occured!" << endl; exit(-1); } str = new char[length]; for(int i = 0; i < length; i++) str[i] = 0; } String::String(char *a){ int n = 0; while(a[n]!='\0') { n++; } length = n; if(length < 0){ cout << "Length < 0 is occured!" << endl; exit(-1); } str = new char[length]; for(int i = 0; i < length; i++){ str[i] = a[i]; } } //copy construct String::String(const String &a){ length = a.length; if(length < 0){ cout << "Length < 0 is occured!" << endl; exit(-1); } str = new char[length]; for(int i = 0; i < length; i++){ str[i] = a.str[i]; } } //destruct String::~String(){ delete [] str; length = 0; } String String::operator=(const String &a){ if(this != &a){ length = a.length; if(length < 0){ cout << "Length < 0 is occured!" << endl; exit(-1); } delete [] str; str = new char[length]; for(int i = 0; i < length; i++){ str[i] = a.str[i]; } } else length = 0; return *this; } char String::operator[](int i){ if(length < 0){ cout << "Length < 0 is occured!" << endl; exit(-1); } return str[i]; } String String::operator+(const String &a){ if(a.length < 0 || length < 0){ cout << "Length < 0 is occured!" << endl; exit(-1); } char *c = new char[length]; for(int i = 0; i < length; i++){ c[i] = str[i]; } length = a.length + length; delete [] str; str = new char[length]; for(int i = 0, j = 0; i < length; i++){ if(i < a.length){ str[i] = a.str[i]; } else{ str[i] = c[j++]; } } return *this; } /*------------------------------------------------ bool operator==(const String a){ if(a.length != length) return false; else{ for(int i = 0; i < length; i++){ if(a.str[i] != str[i]) return false; } } return true; } ---------------------------------------------------*/ int String::lengthof(){ return length; } 註解掉的這段程式碼編譯時他說要兩個參數後來我改掉在編譯時他說要只能一個參數 = = 這是怎麼回事高手煩請指教謝謝!! -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 114.45.24.228

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