我得到了两个文件，一个是.h文件，我必须添加方法/构造函数，另一个是.cpp文件，它将为我完成剩下的工作。
我添加了方法，并且尽我所能，然后我得到了一些帮助，但其余的它仍然无法正常工作。
我收到以下错误：
IntelliSense：没有运算符“==”匹配这些操作数类型是：const String1030 == String1030
错误C2676：binary'=='：'const String1030'没有定义此运算符或转换为预定义可接受的类型 运营商
错误C2572：'String1030 :: String1030'：重新定义默认参数：参数1
我的代码：
#ifndef STRING1030_H
#define STRING1030_H
#include<iostream>
using std::ostream;
using std::istream;
using std::endl;
using std::cerr;
/*
* The class String1030 is for the students to practice implementing
* more class functions and making sure that their implementation
* is reasonable.
*
* It requires some skill in using arrays and overloading operators.
*
* Note that the sentinel value that MUST be part of the storage for our
* strings is '\0'. That is not special, it is just a way to tell future
* readers that we know what we are doing. We could just as well use the
* digit 0, but that can be very confusing.
*/
class String1030
{
public:
// The constructor. The "0" is the digit 0 NOT a
// character. It is used to let us know that
// nothing is being passed to the default constructor.
String1030(const char *buf=0);
//This next is a "copy" constructor. Remember that
//we have to create new storage and then copy
//the array content. We must not just copy the pointer.
String1030(const String1030& oldstring);
// The destructor is needed because we are allocating memory.
// We must deallocate it when the object goes out of
// scope (is destroyed).
~String1030();
String1030& operator=(const String1030& right);
// Allows us to change the element at a certain index.
// refer to the IntList code.
char& operator[](int index);
// Returns the number of characters stored excluding the
// the sentinel value.
int getSize(void) const;
// Resizes the storage. Must include 1 extra space for the
// sentinel value.
void setSize(int newsize);
// Returns a pointer to array storing the string.
const char *getString();
// Replace the existing string with a new one.
void setString(const char *carray);
private:
char *buffer;
int mysize;
};
// Basic constructor.
//
String1030 :: String1030(const char *buff=0): mysize(0), buffer(0)
{
setSize(*buff);
}
//copy constructor
String1030::String1030(const String1030& oldstring) : mysize(0), buffer(0)
{
if (oldstring.getSize() <= 0) {
setSize(0);
}
else {
setSize(oldstring.getSize());
for (int i = 0; i< mysize; i++) {
buffer[i] = oldstring.buffer[i];
}
}
}
// Destructor call
String1030::~String1030()
{
setSize(0);
}
String1030& String1030:: operator = (const String1030& right){
// must take 'address of' the argument to compare it to the
// this pointer.
if (right == *this) {
cerr << "Warning: attempt to copy IntList onto self" << endl;
}
else {
if (right.getSize() +1 <= 0) {
setSize(0);
}
else {
setSize(right.getSize());
for (int i = 0; i< mysize +1 ; i++) {
buffer[i] = right.buffer[i];
}
}
}
return *this; // dereference the pointer to get the object
}
char& String1030::operator[](int index)
{
if (index<0 || index >= mysize + 1) {
cerr << "Attempt to access element outside index bounds"
<< endl;
exit(4); // Maybe not reasonable but what the heck.
}
else {
return buffer[index];
}
}
int String1030::getSize() const
{
return mysize;
}
void String1030::setSize(int newsize)
{
if ( newsize <0) {
cerr << "Warning: attempt to set a size < 0" << endl;
exit(1); // is this reasonable?
}
else {
if (buffer != 0) {
delete[] buffer;
buffer = 0;
mysize = 0;
}
if (newsize != 0) {
buffer = new char[newsize+1];
if (buffer == 0) {
mysize = 0;
cerr << "Warning: unable to allocate enough space for list" << endl;
exit(2);
}
else {
mysize = newsize;
}
}
}
}
// Returns a pointer to array storing the string.
const char* String1030:: getString()
{
return buffer;
}
// Replace the existing string with a new one.
void String1030::setString(const char *carray)
{
int len = 0;
for ( int tmp = 0; carray[tmp] != 0; tmp ++){
len = len + 1;
}
setSize(len);
for(int i=0; i < len +1; i++){
buffer[i] = carray[i];
}
}
#endif
以下是其他代码：
#include<iostream>
#include "String1030.h"
using std::cout;
using std::cin;
int main()
{
// check out the use of the constructors
String1030 s("My string");
String1030 t(s);
String1030 x;
char in_buf[256];
cout << "S size(): " << s.getSize() << endl;
cout << "T size(): " << t.getSize() << endl;
cout << "X size(): " << x.getSize() << endl;
for(int i=0;i<t.getSize();i++)
cout << t[i];
cout << endl;
// check the ability to modify one element of the string
s[2]='5';
for(int i=0;i<s.getSize();i++)
cout << s[i];
cout << endl;
// check the assignment operator
x=s;
cout << "X: " << x.getString() << endl;
// check the size reset.
x.setSize(30);
cout << "Input a string: ";
cin >> in_buf;
x.setString(in_buf);
cout << "\nX: " << x.getString() << endl;
//more checks on resize
//set to a negative value, nothing should change
s.setSize(-8);
cout << "S size(): " << s.getSize() << endl;
//set to 0, should be 0
s.setSize(0);
cout << "S size(): " << s.getSize() << endl;
//read into the 0 length array should NOT have an error
//and should NOT transfer any characters. Output should not
//have any errors either.
cout << "Input a string: ";
cin >> in_buf;
s.setString(in_buf);
cout << "S after cin>>: " << s.getString() << endl;
//reset to something larger than 0
s.setSize(10);
cout << "S size(): " << s.getSize() << endl;
//read should work now
cout << "Input a string: ";
cin >> in_buf;
s.setString(in_buf);
cout << "S after cin>>: " << s.getString() << endl;
//now the assignment return value
x=t=s;
cout << "T: " << t.getString() << endl;
cout << "X: " << x.getString() << endl;
return 0;
}
我不确定遗失了什么，老师说除了需要删除'＆amp;'之外没关系在说运营商的部分=但它不起作用。不知道该怎么办。
答案 0 :(得分：2)
阅读有关操作员过载的here。
鉴于您的错误：
IntelliSense：没有运算符“==”匹配这些操作数类型是：const String1030 == String1030
这一行
(right == *this)
没有实现等于运算符，因此您需要实现一个：
bool operator==(const String1030 & lhs, const String1030& rhs){
/* do actual comparison */
}
答案 1 :(得分：0)
如果您查看==行上方的行
// must take 'address of' the argument to compare it to the
// this pointer."
if (right == *this) {
您目前正在尝试将right的值与*this的值进行比较。您真正想要做的是将指针与right（使用运算符&的地址）与this指针进行比较。
if (&right == this) {
然后您不需要实现值比较运算符（如果您在其他任何地方都不需要它）。