reverse the string

For my driver I have to reverse the strings in a string literal by means of a class called ReverseString. I will show you guys my function below that is supposed to reverse my string. I will also post my test for the string. My output is:
ahsuruP
ahsuruP
ahsuruP

and I am pretty sure that is not the correct output. Why doesn't my function work? Thanks for the help

Code:

ReverseString ReverseString::operator ~()
{
	int k = 0;
	char *temp = buf;
	for(int i = stringlength-1; i>=(stringlength/2); i--)
	{
		swap(temp[k], temp[i]);
		k++;	
	}
	return temp;
}


void test19() {

    system("cls");

    cout << "19. Testing: ReverseString class." << endl << endl;

    csis << "19. Testing: ReverseString class." << endl << endl;

    ReverseString s19("Purusha");

    ReverseString t19;

    s19.setName("s19");

    t19.setName("t19");

    t19 = ~s19;

    s19.print();

    t19.print();

 

    ReverseString u19(~~s19);

    u19.setName("u19");

    u19.print();

    wait();

}

Where is the class?

Originally Posted by siavoshkc

Where is the class?

I posted the function (~operator) but I'll post the entire header and source code:

Code:

//reverse.h

#ifndef ReverseString_H
#define ReverseString_H

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





class ReverseString: public String
{
public:
	ReverseString();
	ReverseString(const ReverseString &rhs);
	ReverseString(const char *str);
	ReverseString operator=(const ReverseString &rhs);
	ReverseString operator~();
};

#endif

// reverse.cpp
#define _CRT_SECURE_NO_DEPRECATE 1	
#include <iostream>
#include <assert.h>
#include <algorithm>
#include "reverse.h"


using namespace std;

ReverseString::ReverseString()
{ }

ReverseString::ReverseString(const ReverseString &rhs)
{ }


ReverseString::ReverseString(const char *str)
{
	name = NULL;
	assert( str != 0);
	stringlength = strlen(str);
	size = stringlength + 1;
	buf = new char[size];
	strcpy(buf, str);
}

ReverseString ReverseString::operator =(const ReverseString &rhs)
{
	if(this != &rhs)
	{
		delete []buf;
		stringlength = rhs.stringlength;
		size = stringlength + 1;
		buf = new char[size];
		strcpy(buf, rhs.buf);
	}
	return *this;
}

ReverseString ReverseString::operator ~()
{
	int k = 0;
	char *temp = buf;
	for(int i = stringlength-1; i>=(stringlength/2); i--)
	{
		swap(temp[k], temp[i]);
		k++;	
	}
	return temp;
}

Originally Posted by BKurosawa

For my driver I have to reverse the strings in a string literal by means of a class called ReverseString. I will show you guys my function below that is supposed to reverse my string. I will also post my test for the string. My output is:
ahsuruP
ahsuruP
ahsuruP

and I am pretty sure that is not the correct output. Why doesn't my function work? Thanks for the help

So what is the output you expect?

Your operator~ does modifiy the original string which is probably not what you wanted...

--
Mats

Originally Posted by matsp

So what is the output you expect?

Your operator~ does modifiy the original string which is probably not what you wanted...

--
Mats

I have the test up there. I might be wrong but I think that the output should be:
Purusha
ahsuruP
Purusha

How do I fix it? Thanks

What's the temp variable in your operator~ function? Where does it point, and how do you think you should fix it?

--
Mats

Originally Posted by matsp

What's the temp variable in your operator~ function? Where does it point, and how do you think you should fix it?

--
Mats

The temp points to buf... why is that a problem?

Originally Posted by BKurosawa

The temp points to buf... why is that a problem?

In you line "t19 = ~s19;", what is buf? What gets modified in that line?

--
Mats

Originally Posted by matsp

In you line "t19 = ~s19;", what is buf? What gets modified in that line?

--
Mats

What if I do this? :

Code:

ReverseString ReverseString::operator ~()
{
	int k = 0;
	char *temp = buf;
	for(int i = stringlength-1; i>=(stringlength/2); i--)
	{
		swap(temp[k], temp[i]);
		k++;	
	}
	ReverseString object(temp);
	return object;
}

Sorry, but did you think that through, or just randomly guess ?

No, that's not quite right, but you have the sort of right idea. The order in which you do things is a bit wrong, that's it.

--
Mats

>> The order in which you do things is a bit wrong.

How so?

Instead of asking us to solve your coding problems, how about you think about what actually happens in the code... If you UNDERSTAND what you are doing, then it's going to work so much better for you in the future. You seem to prefer the method of "randomly change the code and hope that either it fixes the problem, or someone tells you how to do it" - this is NOT the right way to learn programming.

--
Mats