重载操作符与复制构造函数~头疼
#include <iostream>using std::ostream;
using std::istream;
#ifndef STRING1_H_
#define STRING1_H_
class String
{
private:
char * str; // pointer to string
int len; // length of string
static int num_strings; // number of objects
enum {CINLIM=80}; // cin input limit //定义了以后编译时候说没有定义这个常量
public:
// constructors and other methods
String(const char * s); // constructor
String(); // default constructor
String(const String &); // copy constructor
~String(); // destructor
int length () const { return len; }
// overloaded operator methods
String & operator=(const String &);
String & operator=(const char *);
char & operator[](int i);
const char & operator[](int i) const;
// overloaded operator friends
friend bool operator<(const String &st, const String &st2);
friend bool operator>(const String &st1, const String &st2);
friend bool operator==(const String &st, const String &st2);
friend ostream & operator<<(ostream & os, const String & st);
friend istream & operator>>(istream & is, String & st);
// static function
static int HowMany();
};
#endif
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// string1.cpp -- String class methods
#include <cstring> // string.h for some
#include "string1.h" // includes <iostream>
using std::cin;
using std::cout;
// initializing static class member
int String::num_strings = 0;
// static method
int String::HowMany()
{
return num_strings;
}
// class methods
String::String(const char * s) // construct String from C string
{
len = strlen(s); // set size
str = new char[len + 1]; // allot storage
strcpy(str, s); // initialize pointer
num_strings++; // set object count
}
String::String() // default constructor
{
len = 4;
str = new char[1];
str[0] = '\0'; // default string
num_strings++;
}
String::String(const String & st)
{
num_strings++; // handle static member update
len = st.len; // same length
str = new char [len + 1]; // allot space
strcpy(str, st.str); // copy string to new location
}
String::~String() // necessary destructor
{
--num_strings; // required
delete [] str; // required
}
// overloaded operator methods
// assign a String to a String
String & String::operator=(const String & st)
{
if (this == &st)
return *this;
delete [] str;
len = st.len;
str = new char[len + 1];
strcpy(str, st.str);
return *this;
}
// assign a C string to a String
String & String::operator=(const char * s)
{
delete [] str;
len = strlen(s);
str = new char[len + 1];
strcpy(str, s);
return *this;
}
// read-write char access for non-const String
char & String::operator[](int i)
{
return str[i];
}
// read-only char access for const String
const char & String::operator[](int i) const
{
return str[i];
}
// overloaded operator friends
bool operator<(const String &st1, const String &st2)
{
return (strcmp(st1.str, st2.str) < 0);
}
bool operator>(const String &st1, const String &st2)
{
return st2.str < st1.str;
}
bool operator==(const String &st1, const String &st2)
{
return (strcmp(st1.str, st2.str) == 0);
}
// simple String output
ostream & operator<<(ostream & os, const String & st)
{
os << st.str;
return os;
}
// quick and dirty String input
istream & operator>>(istream & is, String & st)
{
char temp[CINLIM]; //编译之后说没有定义 CINLIM
is.get(temp,CINLIM);
if (is)
st = temp;
while (is && is.get() != '\n')
continue;
return is;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#include <iostream>
#include "string1.h"
const int ArSize = 10;
const int MaxLen =81;
int main()
{
using std::cout;
using std::cin;
using std::endl;
String name;
cout <<"Hi, what's your name?\n>> ";
cin >> name;
cout << name << ", please enter up to " << ArSize
<< " short sayings <empty line to quit>:\n";
String sayings[ArSize]; // array of objects
char temp[MaxLen]; // temporary string storage
int i;
for (i = 0; i < ArSize; i++)
{
cout << i+1 << ": ";
cin.get(temp, MaxLen);
while (cin && cin.get() != '\n')
continue;
if (!cin || temp[0] == '\0') // empty line?
break; // i not incremented
else
sayings[i] = temp; // overloaded assignment
}
int total = i; // total # of lines read
cout << "Here are your sayings:\n";
for (i = 0; i < total; i++)
cout << sayings[i][0] << ": " << sayings[i] << endl;
int shortest = 0;
int first = 0;
for (i = 1; i < total; i++)
{
if (sayings[i].length() < sayings[shortest].length())
shortest = i;
if (sayings[i] < sayings[first])
first = i;
}
cout << "Shortest saying:\n" << sayings[shortest] << endl;;
cout << "First alphabetically:\n" << sayings[first] << endl;
cout << "This program used "<< String::HowMany()
<< " String objects. Bye.\n";
return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
eleting intermediate files and output files for project 'zy_12_5 - Win32 Debug'.
--------------------Configuration: zy_12_5 - Win32 Debug--------------------
Compiling...
string1.cpp
d:\c++程序\zy_12_5\string1.cpp(111) : error C2065: 'CINLIM' : undeclared identifier
d:\c++程序\zy_12_5\string1.cpp(111) : error C2057: expected constant expression
d:\c++程序\zy_12_5\string1.cpp(111) : error C2466: cannot allocate an array of constant size 0
d:\c++程序\zy_12_5\string1.cpp(111) : error C2133: 'temp' : unknown size
1.cpp
Error executing cl.exe.
zy_12_5.exe - 4 error(s), 0 warning(s)
头疼很~不知道怎么回事
你的回复是我最大的学习动力
