A custom String Class

[hoser2001]

My entire programming experience has been based in C#, so my skills dealing with creating classes is somewhat limited, especially in C++.

I have to create a really simple string class that just does a few operations
(head and tail functions, concatenation operator, assignment operator and the input and output operators >> <<)

I also need a default constructor, and two other constructors for handling single characters and copying strings.

I want to be able to include it at the top of a program.

If anyone has any suggestions as to the best way to approach creating a class with just these simple requirements I would greatly appreciate any help.

Thanks in advance!

[hoser2001]

Alright, I got my class put together, but I have an insane amount of compiler errors, and I don't get why most of them are there. I mostly followed examples online but for the most part I think it's right. I'm sure some of the errors are easily fixed, however I know I am missing a few major concepts here!

#include <iostream>

using namespace std;

class Cstring
{
private:
 //array that will hold the strings
 char array[50];
public: 
 //default constructor
 Cstring();   
 //constructor that turns a single character into a string  
 Cstring(char&);
 //constructor that creates a copy of a string
 Cstring(Cstring&);
//////////////////////////////////////
 //overloaded operators for strings
//////////////////////////////////////
//this operator adds a single characters to the end of a string
 friend Cstring operator + (Cstring&);
//this operator copies a string into a result string
 friend Cstring operator = (Cstring&);
//these are of course the input and output operators
 friend Cstring operator >> (Cstring&);
 friend Cstring operator << (Cstring&); 
 //function that returns the first character of the string   
 char head();
 //function that returns the string with the first character removed
 Cstring tail();
};

char Cstring::head()
{
 return array[0];
}

Cstring Cstring::tail()
{
 Cstring temp;
 for(int i=1; i<50; i++;)
 {
  temp.array[i] = array[i];     
 }
 return temp;  
}

Cstring::Cstring()
{
 for(int i=0; i<50; i++;)
 array[i]=' ';
}

Cstring::Cstring(char &this)
{
 array[0] = this;
 for (int i=1; i<50; i++;)
 array[i] = ' ';
}

Cstring::Cstring(Cstring &other)
{
 for (int i=0; i<50; i++;)
 array[i] = other.array[i];
}

Cstring Cstring::operator+(Cstring &left, char &right)
{
 Cstring temp;
 for(int i=0; i<50; i++)
   temp.array[i] = left.array[i];
         
 for(i=0; i<50; i++)
 {
  if(temp.array[i]==' ')
  {
   temp.array[i] = right;
   break
  }
 }
 return temp;           
}

Cstring::operator=(Cstring &left, Cstring &right)
{
 Cstring temp;
 temp.array[i] = right.array[i];
}

ostream&::operator<<(ostream& output, Cstring &right)
{
 for(int i=0; i<50; i++)
 {
  if(right.array[i] != ' ')
  output << right.array[i];
 }
}

istream&::operator>>(istream& input, Cstring &right)
{
 Cstring temp;
 input.getline(temp.array,50);
 return temp;
}

[Void]

Hey, what compiler are you using?

[hoser2001]

bloodshed dev c++ 4.9.9.1

[hoser2001]

Ok, I started over and decided to compile little bit at a time instead of cranking stuff out and trying to debug the whole thing... This is how far Ive gotten so far. I commented out the overloading of the = sign because I have no idea whats wrong with that, and I left in the main function because I dont know how to compile it without it, however the rest of it works until I try adding the method for overloading the + operator at which time I get this error message: "..... must take either zero or one argument"

#include <cstdlib>
#include <iostream>

using namespace std;

class Cstring
{
private:
 //array that will hold the strings
 char array[50];
public: 
 //default constructor
 Cstring();   
 //constructor that turns a single character into a string  
 Cstring(char&);
 //constructor that creates a copy of a string
 Cstring(Cstring&);
 //////////////////////////////////
 //overloaded operators for strings
 //////////////////////////////////
 //this operator adds a single character to the end of a string
 friend Cstring operator + (Cstring&);
 //this operator stores a copy of a string in a result string
 //friend Cstring operator = (Cstring&); //wtf is wrong with this????
 //these are my input/output operators
 friend Cstring operator >> (istream&, Cstring&);
 friend Cstring operator << (ostream&, Cstring&); 
 //function that returns the first character of the string   
 char head();
 //function that returns the string with the first character removed
 Cstring tail();
};

/////////////////////////////////////
//Constructors
////////////////////////////////////

//default constructor
Cstring::Cstring()
{
 for(int i=0; i<50; i++)
 array[i]=' ';
}

//constructor that makes character a string
Cstring::Cstring(char &stuff)
{
 array[0] = stuff;
 for (int i=1; i<50; i++)
 array[i] = ' ';
}

//constructor that copies string to result string
Cstring::Cstring(Cstring &other)
{
 for (int i=0; i<50; i++)
 array[i] = other.array[i];
}

/////////////////////////////////////
//Functions
/////////////////////////////////////

//this is the head function that returns first character of string
char Cstring::head()
{
 return array[0];
}

//this is the tail function that returns the string without the first character
Cstring Cstring::tail()
{
 Cstring temp;
 for(int i=1; i<50; i++)
 {
  temp.array[i] = array[i];     
 }
 return temp;  
}

///////////////////////////////////
//Operator Overloads
///////////////////////////////////

Cstring Cstring::operator+(Cstring &left, char &right)
{
 Cstring temp;
 for(int i=0; i<50; i++)
   temp.array[i] = left.array[i];
         
 for(int j=0; j<50; j++)
 {
  if(temp.array[j]==' ')
  {
   temp.array[j] = right;
   break;
  }
 }
 return temp;           
}





int main(int argc, char *argv[])
{
    system("PAUSE");
    return EXIT_SUCCESS;
}

[hoser2001]

Alright, I finally got my class to compile, and I'm pretty sure everything is alright, but now I have to use this class in another program in which I perform a couple of recursive operations. RECURSION PWNS ME....

#include <cstdlib>
#include <iostream>

using namespace std;

class Cstring
{
private:
 //array that will hold the strings
 char array[50];
public: 
 //default constructor
 Cstring();   
 //constructor that turns a single character into a string  
 Cstring(char&);
 //constructor that creates a copy of a string
 Cstring(Cstring&);
 //////////////////////////////////
 //overloaded operators for strings
 //////////////////////////////////
 //this operator adds a single character to the end of a string
 friend Cstring operator + (Cstring left, const char right);
 //this operator stores a copy of a string in a result string
 Cstring Cstring::operator = (Cstring& right);
 //these are my input/output operators
 friend istream& operator >> (istream& input, Cstring& right);
 friend ostream& operator << (ostream& output, Cstring& right); 
 //function that returns the first character of the string   
 char head();
 //function that returns the string with the first character removed
 Cstring tail();
};

/////////////////////////////////////
//Constructors
////////////////////////////////////

//default constructor
Cstring::Cstring()
{
 for(int i=0; i<50; i++)
 array[i]= ' ';
}

//constructor that makes character a string
Cstring::Cstring(char &stuff)
{
 array[0] = stuff;
 for (int i=1; i<50; i++)
 array[i] = ' ';
}

//constructor that copies string to result string
Cstring::Cstring(Cstring &other)
{
 for (int i=0; i<50; i++)
 array[i] = other.array[i];
}

/////////////////////////////////////
//Functions
/////////////////////////////////////

//this is the head function that returns first character of string
char Cstring::head()
{
 return array[0];
}

//this is the tail function that returns the string without the first character
Cstring Cstring::tail()
{
 Cstring temp;
 for(int i=1; i<50; i++)
 {
  temp.array[i] = array[i];     
 }
 return temp;  
}

///////////////////////////////////
//Operator Overloads
///////////////////////////////////

Cstring operator+ (Cstring left, char right)
{
 Cstring temp;
 for(int i=0; i<50; i++)
   temp.array[i] = left.array[i];
         
 for(int j=0; j<50; j++)
 {
  if(temp.array[j]==' ')
  {
   temp.array[j] = right;
   break;
  }
 }
 return temp;           
}

ostream& operator<<(ostream& output, Cstring &right)
{
 for(int i=0; i<50; i++)
 {
  if(right.array[i] != ' ')
  output << right.array[i];
 }
}

istream& operator>>(istream& input, Cstring &right)
{
 Cstring temp;
 input.getline(temp.array,50);
 input >> temp;
}
Cstring Cstring::operator=(Cstring& right)
{
 int i=0;
 Cstring temp;
 temp.array[i] = right.array[i];
 return temp;
}

I have 3 recursive operations I need to perform:
1.)a function that returns the reverse of a string
2.)a function that concatenates the reverse of a string onto the original string
3.)a function that tests if a certain string is the prefix of another string

If anyone can point me in some possible dirrection, or even try to explain to me exactly how it is recursion works I would appreciate the help greatly!!!!

[Ronin]

That is a neat function. I'm not sure I will get the syntax right here but couldn't you use this to return the reverse of a string: (I'm also not sure of the array functions)

array[0] = array;
rArray[0] = array;
int count=0;

for (int i=length(array); i>=0; i--) 
{
     rArray[count] = array[i];
     count++;
}

I could be way off though.

[WingedPanther]

You have most of what you need for doing a reverse.
The basic idea of recursion is to break a task into many smaller steps that are identical. For instance, if you want to compute a factorial (5! = 5*4*3*2*1), one way to do it is to say n! = n*(n-1)!, and note that 0!=1.

For reversing your string, just note that MyString.rev() = MyString.tail().rev()+MyString.head(), and a single character string is its own reverse.

Once you have part 1 done, part 2 is trivial. For testing the prefix, just test the heads and tails of the strings.

[Crane]

that is a nice looking class. May I ask why you are recreating a string class though?

[WingedPanther]

It's a pretty standard programming project for classes.