pex6_8.cpp

数据结构C++代码,经典代码,受益多多,希望大家多多支持

#include <iostream.h>
#include <string.h>

class String
{
	private:
		char str[256];
	public:
		// constructor
		String(char s[] = "");

		int Length(void) const;			// string length
		void CString(char s[]) const;	// copy string to C++ array s

		// *****Stream I/O *****
		friend ostream& operator<< (ostream& ostr, const String& s);
		// Read whitespace separated strings
		friend istream& operator>> (istream& istr, String& s);

		// ***** relational operators *****
		int operator== (String& s) const;	// String == String

		// ***** string  concatenation *****
		String operator+ (String& s) const;
};

// constructor. copy C++ string s to data member str
String::String(char s[])
{
	strcpy(str,s);
}

// return the length of the string
int String::Length(void) const
{
	return strlen(str);
}

// copy the data member str to the C++ string s
void String::CString(char s[]) const
{
	strcpy(s,str);
}

// stream output
ostream& operator<< (ostream& ostr, const String& s)
{
	cout << s.str;
	
	return ostr;
}

// input whitespace separated strings
istream& operator>> (istream& istr, String& s)
{
	istr >> s.str;
	
	return istr;
}

// test current object and s for equality
int String::operator== (String& s) const
{
	return strcmp(str,s.str) == 0;
}

// return a String object that consists of s
// concatenated onto the current object
String String::operator+ (String& s) const
{
	String temp;
	
	// copy str to temp.str
	strcpy(temp.str,str);
	// concatenate s.str onto the end of temp.str
	strcat(temp.str,s.str);
	
	// return the new object
	return temp;
}

// test the class by running the following program.

void main(void)
{
	String S1("It is a "), S2("beautiful day!"), S3;
	char s[30];

	// note there is no blank after the 'a'. if the
	// blank is present, the strings are equal
	if (S1 == String("It is a"))
		cout << "Equality test O.K." << endl;
	else
		cout << "Equality test failed." << endl;
	

	cout << "The length of S1 = " << S1.Length() << endl;

	cout << "Enter a string S3: ";
	cin >> S3;
	// note that it is a good idea to echo the input string
	cout << S3 << endl;

	S3 = S1 + S2;
	cout << "The concatenation of S1 and S2 is '"
		 << S3 << "'" << endl;

	S3.CString(s);
	cout << "The C++ string stored in S3 is '" << s << "'" << endl;
}

/*
<Run>

Equality test failed.
The length of S1 = 8
Enter a string S3: wonderful
wonderful
The concatenation of S1 and S2 is It is a beautiful day!
The C++ string stored in S3 is 'It is a beautiful day!'
*/