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Lots of problems with String class

InfiniteLoop (16)
I had an assignment where I had to implement a string class and get two test files to run. Long story short, I think I've completely mangled this class. I'm getting a ton of Linked errors, and I have no idea what to do with this program. Could someone help?

There's some separate files, so it's a little long. 

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#ifndef STRING_H
#define STRING_H
// String.h
#include <iostream>
using namespace std;

class String {
        int size;
        char * buffer;
public:
        String();
        String(const String &);
        String(const char *);
        ~String();        
        int length() const;
        void resize(unsigned int, char);
        void insert(unsigned int, String&);
        char& operator[] (unsigned int);
        void operator = (const String&);
        void operator += (const String&);

	// other methods
        friend bool operator==(const String &, const String &);
        friend bool operator<=(const String &, const String &);
        friend bool operator<(const String &, const String &);
        friend ostream & operator<<(ostream &, const String &);
};
#endif 


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#include "String.h"
#include <cassert>
#include <iostream>

String::String()
{
    buffer = 0;
    resize(0, ' ');
}

String::String(const String& s)
{
    size = s.size;
    buffer = new char[size];
    for(int i = 0; i < size; i++){
        buffer[i] = s.buffer[i];
    }
}

String::String(const char *p)
{
    int p_size = 0;
    for(const char *q = p; *q; q++){
        p_size++;
    }
    buffer = new char[p_size];
    for(int i=0;i<p_size;i++){
        size = p_size;
    }
}

String::~String()
{
    delete[] buffer;
}

int String::length()
{
    int i = 0;
    while(buffer[i] != '\0'){
        i++;
    }
    return i;
}

void String::resize(unsigned int newlength, char pad)
{
    if (buffer == 0){
        size = 0;
    }
    if (newlength < size){
        buffer[newlength = '\0'];
    }
    else{
        int i;
        char * newbuffer = new char[newlength + 1];
        assert (newbuffer != 0);
        for(i=0; i < size && buffer[i] != '\0'; i++){
            newbuffer[i] = buffer[i];
        }
        for( ; i < newlength;i++){
            newbuffer[i] = pad;
        }
        newbuffer[i] = '\0';
        if(buffer != 0){
            delete[] buffer;
        }
        buffer = newbuffer;
        size = newlength; 
    }
}

void String::insert(unsigned int position, String &text)
{
    int lgt = length();
    int addlength = text.length();
    int newlength = lgt + addlength;
    resize(newlength, '\0');
    for(int i = lgt; i >= position; i--){
        buffer[i + addlength] = buffer[i];
    }
    for (int i = 0; i < addlength; i++){
        buffer[position + i] = text[i];
    }
}

char & String::operator[](unsigned int index)
{
    assert (index <= size);
    return buffer[index];
}

void String::operator = (String & p){
    resize(p.length(), ' ');
    strcpy(buffer, p.buffer);
}

void String::operator += (const String & s){
    int temp_size=size+s.size;
    char*temp;
    temp=new char[temp_size];
    int i;
    for(i=0;i<size;i++)
    {
        temp[i]=buffer[i];
    }
    for(int j=0;j<s.size;j++,i++)
    {
        temp[i]=s.buffer[j];
    }
    delete[]buffer;
    size=temp_size;
    buffer=temp;
    return *this;
}
}

bool operator==(const String &S1, const String &S2)
{
   	if(S1.size == S2.size)
	{
		int counter1 = S1.size;
		int counter2 = 0;
		int i = 0;
		while(i != counter1)
		{
			if(S1.buffer[i] != S2.buffer[i]){
                counter2++;
            }
			i++;
		}
		if(counter2 != 0) {
            return false;
        }
		else{
            return true;
        }
	}
	else {
        return false;
    }
}

bool operator<=(const String &S1, const String &S2){
    if(S1.size <= S2.size){
        int counter1 = S1.size;
        int counter2 = 0;
        int i = 0;
        while(i != counter1){
            if(S1.buffer[i] <= S2.buffer[i]){
                counter2++;
            }
            i++;
        }
        if(counter2 != 0){
            return true;
        }
        else{
            return false;
        }
    }
    else{
        return false;
    }
}

ostream& operator<< ( ostream& os, const String& s)
{
    
        os << s.size;
        return os;
    
}


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// String_test.cpp

#include <iostream>
#include <cassert>
#include "String.h"

using namespace std;

int main()
{
   String s1; // s1 == ""
   assert(s1.length() == 0);

   String s2("hi");  // s2 == "hi"
   assert(s2.length() == 2);

   String s3(s2);  // s3 == "hi"
   assert(s3.length() == 2);
   assert(s3[0] == 'h');
   assert(s3[1] == 'i');

   s1 = s2;  // s1 == "hi"
   assert(s1 == s2);

   s3 = "bye";  // s3 == "bye"
   assert(s3.length() == 3);
   assert(s3[0] == 'b');
   assert(s3[1] == 'y');
   assert(s3[2] == 'e');
   
   s1 += "re";  // s1 == "hire"
   assert(s1 == "hire");

   s1 += "d"; // s1 == "hired"
   assert(not (s1 == "hire"));

   cout << "SUCCESS" << endl;
}


And the errors it's giving me:


[Linker Error] undefined reference to `String::String(char const*)'
[Linker Error] undefined reference to `String::String(char const*)'
[Linker Error] undefined reference to `operator==(String const&, String const&)'
[Linker Error] undefined reference to `operator<=(String const&, String const&)'
[Linker Error] undefined reference to `operator<<(std::ostream&, String const&)'
[Linker Error] undefined reference to `operator<<(std::ostream&, String const&)'
[Linker Error] undefined reference to `operator<<(std::ostream&, String const&)'
[Linker Error] undefined reference to `operator<<(std::ostream&, String const&)'
[Linker Error] undefined reference to `operator<<(std::ostream&, String const&)'
more undefined references to `operator<<(std::ostream&, String const&)' follow
[Linker Error] undefined reference to `String::~String()'
[Linker Error] undefined reference to `String::~String()'
[Linker Error] undefined reference to `String::~String()'
[Linker Error] undefined reference to `String::~String()'
ld returned 1 exit status
Smac89 (1727)
Your String_test.cpp should include String.cpp rather than String.h.

After that is fixed, there are a lot of syntax errors in your String class that you need to fix. To mention a few:

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if (newlength < size){
    buffer[newlength = '\0'];
}



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void String::operator += (const String & s){
    ...
    return *this;
}
Last edited on
Peter87 (11234)
Smac89 wrote:
Your String_test.cpp should include String.cpp rather than String.h.

Don't do that. Learn how to link a program properly instead. If you use an IDE all you normally have to do is to make sure all the files have been added to the same project.
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