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Feb 1st, 2005

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error in user defined string class

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I almost got my user defined string class to work but not quite. When I execute the program, I get a memory error. Code is as follows.

#include <iostream>

using namespace std;

class String {
char *str; //pointer to character block
public:
String();
String (char *s);
void setString (char *s);
int stringLength();
char getString();

};
String:

tring() {}

String:

tring(char *s)
{
int length=strlen(s); //length of string
str=new char[length+1]; //increments length of string
strcpy(str,s); //copies s to str
cout<<str<<'\n';
}

void String::setString(char *s)
{
int length=strlen(s); //length of string
str=new char[length+1]; //increments length of string
strcpy(str,s); //copies s to str
cout<<str<<'\n';
}

int String::stringLength()
{
int length=strlen(str);;

return length;
}

char String:: getString()
{
char *s;
int length=strlen(s); //length of string
str=new char[length+1]; //increments length of string
strcpy(str,s); //copies s to str
cout<<str<<'\n';
return *str;
}

int main()
{
String s1="Hello World";
String s2;

s2.setString("THis is a string");
cout<<"string 1 is "<<s1.stringLength()<<"characters long"<< endl;
cout << "string 1 is " << s1.getString()<< endl;

return 0;
}

I think it has to do with my getstring() function. The reason I have return returning str is because it should be returning my string as shown in the main program. But perhaps I have overlooked something.
Error I get when executed is that memory could not be read.
Thanks in advance.

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supersonic

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Feb 1st, 2005

Re: error in user defined string class

Please use Code tags when posting code it makes helping much better.

prog-bman

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Feb 1st, 2005

Re: error in user defined string class

Here's a little string class I wrote. I am not sure how good it is but it works

(Toggle Plain Text)

#include <iostream>

namespace myString
{
  
  class string
  {
    public:
      string();
      string(char *s);
      void operator =(char *s);
      int length();
      char *getString();
    private:
      char *str;
  };
  
  string::string()
  {
    
    
  }
    
  string::string(char *s)
  {
    
    str = new char[sizeof(s)];
    str = s;
    
  }
  
  void string::operator =(char *s)
  {
    
    str = new char[sizeof(s)];
    str = s;
    
  }
  
  int string::length()
  {
    
    return (sizeof(str) + 1);
             
  }
  
  char *string::getString()
  {  
      
    return str;
    
  }
    
}

int main()
{
  
  myString::string mystring;
  mystring = "Hello";
  std::cout<<mystring.getString()<<std::endl;
  std::cin.get();
  
  return 0;
  
}

prog-bman

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Feb 1st, 2005

Re: error in user defined string class

ok here it is with the code tags. sorry

C++ Syntax (Toggle Plain Text)
#include <iostream>
 
using namespace std;
 
class String {
char *str; //pointer to character block
public:
String();
String (char *s);
void setString (char *s);
int stringLength();
char getString();
 
 
};
String::String() {}
 
 
String::String(char *s)
{
int length=strlen(s); //length of string
str=new char[length+1]; //increments length of string
strcpy(str,s); //copies s to str
cout<<str<<'\n';
}
 
void String::setString(char *s)
{
int length=strlen(s); //length of string
str=new char[length+1]; //increments length of string
strcpy(str,s); //copies s to str
cout<<str<<'\n';
}
 
int String::stringLength()
{
int length=strlen(str);;
 
return length;
}
 
char String:: getString()
{
char *s;
int length=strlen(s); //length of string
str=new char[length+1]; //increments length of string
strcpy(str,s); //copies s to str
cout<<str<<'\n';
return *str;
}
 
 
 
int main()
{
String s1="Hello World";
String s2;
 
s2.setString("THis is a string");
cout<<"string 1 is "<<s1.stringLength()<<"characters long"<< endl;
cout << "string 1 is " << s1.getString()<< endl;
 
 
return 0;
}
#include <iostream>

using namespace std;

class String {
char *str; //pointer to character block
public:
String();
String (char *s);
void setString (char *s);
int stringLength();
char getString();


};
String::String() {}


String::String(char *s)
{
int length=strlen(s); //length of string
str=new char[length+1]; //increments length of string
strcpy(str,s); //copies s to str
cout<<str<<'\n';
}

void String::setString(char *s)
{
int length=strlen(s); //length of string
str=new char[length+1]; //increments length of string
strcpy(str,s); //copies s to str
cout<<str<<'\n';
}

int String::stringLength()
{
int length=strlen(str);;

return length;
}

char String:: getString()
{
char *s;
int length=strlen(s); //length of string
str=new char[length+1]; //increments length of string
strcpy(str,s); //copies s to str
cout<<str<<'\n';
return *str;
}



int main()
{
String s1="Hello World";
String s2;

s2.setString("THis is a string");
cout<<"string 1 is "<<s1.stringLength()<<"characters long"<< endl;
cout << "string 1 is " << s1.getString()<< endl;


return 0;
}

Thanks

supersonic

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Feb 1st, 2005

Re: error in user defined string class

Quote originally posted by prog-bman ...

Here's a little string class I wrote. I am not sure how good it is but it works
(Toggle Plain Text)
#include <iostream>

namespace myString
{
  
  class string
  {
    public:
      string();
      string(char *s);
      void operator =(char *s);
      int length();
      char *getString();
    private:
      char *str;
  };
  
  string::string()
  {
    
    
  }
    
  string::string(char *s)
  {
    
    str = new char[sizeof(s)];
    str = s;
    
  }
  
  void string::operator =(char *s)
  {
    
    str = new char[sizeof(s)];
    str = s;
    
  }
  
  int string::length()
  {
    
    return (sizeof(str) + 1);
             
  }
  
  char *string::getString()
  {  
      
    return str;
    
  }
    
}

int main()
{
  
  myString::string mystring;
  mystring = "Hello";
  std::cout<<mystring.getString()<<std::endl;
  std::cin.get();
  
  return 0;
  
}
#include <iostream> namespace myString { class string { public: string(); string(char *s); void operator =(char *s); int length(); char *getString(); private: char *str; }; string::string() { } string::string(char *s) { str = new char[sizeof(s)]; str = s; } void string::operator =(char *s) { str = new char[sizeof(s)]; str = s; } int string::length() { return (sizeof(str) + 1); } char *string::getString() { return str; } } int main() { myString::string mystring; mystring = "Hello"; std::cout<<mystring.getString()<<std::endl; std::cin.get(); return 0; }

Thanks. I executed it and did notget any errors which is a good thing

ANd you had some differnet ideas that I will look at when I get to work and have more time in front of my laptop (hopefully).

supersonic

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