Write an example of C++ in C
- 2020-05-26 09:53:14
- OfStack
The following is the simulation implementation of string related functions, it includes the following functions:
String (const char * s); // USES a string to initialize an object
String (); // default constructor
String(const String
&
s); // copy constructor, which initializes the object using the String type
~ String (); // destructor
int length (); // returns the length of a string of type String
String
&
operator=(const String
&
s); // overload = operator.
String
&
operator=(const char *);
char
&
operator [] (int i); // overloads the [] operator
const char
&
operator[](int i) const;
friend bool operator
<
(const String
&
st,const String
&
st2); / / overloaded
<
Operator to compare the size of a string of type String.
friend bool operator
>
(const String
&
st,const String
&
st2);
friend bool operator==(const String
&
st,const String
&
st2); // overloading == operator to determine if two String objects are equal
friend ostream
&
operator
<
<
(ostream
&
os,const String
&
st2); // overloaded output function
friend istream
&
operator
>
>
(istream
&
is,String
&
st2); // overload the input function
static int HowMang()// returns the total number of String class objects generated.
String.h:
#ifndef STRING_H_INCLUDED
#define STRING_H_INCLUDED
#include"iostream"
#include<string.h>
using std::ostream;
using std::istream;
class String{
private:
char * str;
int len;
public:
static int num_strings;
static const int CINLM=80;
String(const char * s);
String();
String(const String & s);
~String();
int length();
String & operator=(const String & s);
String & operator=(const char *);
char & operator[](int i);
const char & operator[](int i) const;
friend bool operator<(const String & st,const String & st2);
friend bool operator>(const String & st,const String & st2);
friend bool operator==(const String & st,const String & st2);
friend ostream & operator<<(ostream & os,const String & st2);
friend istream & operator>>(istream & is,String & st2);
static int HowMang()
{
return num_strings;
}
};
#endif // STRING_H_INCLUDED
String.cpp:
#include<iostream>
#include"String.h"
#include"string.h"
using namespace std;
int String::num_strings=0;
int String::length()
{
return this->len;
}
String::String(const char * s)
{
len=strlen(s);
str=new char[len+1];
num_strings++;
}
String::String()
{
str=0;
len=0;
num_strings++;
}
String::String(const String & s)
{
num_strings++;
len=strlen(s.str);
str=new char[len+1];
strcpy(str,s.str);
}
String::~String()
{
--num_strings;
delete [] str;
len=0;
}
String & String::operator=(const String & s)
{
if(this==&s)
return *this;
delete [] str;
len=strlen(s.str);
str=new char[len+1];
strcpy(str,s.str);
// num_strings++;
}
String & String::operator=(const char * s)
{
len=strlen(s);
str=new char[len+1];
strcpy(str,s);
// num_strings++;
}
char & String::operator[](int i)
{
return str[i];
}
const char & String::operator[](int i) const
{
return str[i];
}
bool operator<(const String & st,const String & st2)
{
if(strcmp(st.str,st2.str)<0)
return true;
else
return false;
}
bool operator>(const String & st,const String & st2)
{
return (st<st2)==false;
}
bool operator==(const String & st,const String & st2)
{
if(strcmp(st.str,st2.str)>0)
return true;
else
return false;
}
ostream & operator<<(ostream & os,const String & st2)
{
os<<st2.str;
return os;
}
istream & operator>>(istream & is,String & st2)
{
char temp[String::CINLM];
is.get(temp,String::CINLM);
if(is)
st2=temp;
while(is&&is.get()!='\n')
continue;
return is;
}
main.cpp:
#include <iostream>
#include"String.h"
using namespace std;
int main()
{
String name[5];
char temp[10];
int i;
for(i=0;i<5;i++)
{
cin.get(temp,10);
while(cin&&cin.get()!='\n')
continue;
if(!cin&&temp[0]=='\0')// If it's an empty string, cin for false
break;
else
name[i]=temp;
}
int total=i;
int firs=0,shor=0;
if(total<0)
{
cout<<" No input "<<endl;
}else{
for(i=0;i<total;i++)
{
cout<<name[i][0]<<":"<<name[i]<<endl;
}
for(i=0;i<total;i++)
{
if(name[i]<name[firs])
firs=i;
if(name[i].length()<name[shor].length())
shor=name[i].length();
}
}
cout<<" The shortest string is: "<<name[shor]<<endl;
cout<<" The first string is: "<<name[firs]<<endl;
return 0;
}