pointer problem

[DOOO]

hello

I have an error in my cod which is trying to sort an arry using pointer i'd be grateful if any one help me to solve my problem and here is my code

[CODE=cpp]/*************** *************** *************** *************** *************** ******/

#include <list>
#include<iostre am>
#include <algorithm>

using namespace std;

//////////////////////////////////////////
double size(double* begin,double* end)
{
return ((end-begin)+1);
}
//////////////////////////////////////////
void swap_ptr(double * a, double* b) {
double temp = *a;
*a = *b;
*b = temp;
}

//////////////////////////////////////

void sort(double *begin, double *end)
{

for(int i=0;i<size(begi n,end);i++)

{

if(*(begin+i)>* (begin+i+1))

{

swap_ptr((begin +i),((begin+i+1 )));

}

}

}
///////////////////////
int main()
{
double* arr = new double[5];

for(int j=0;j<5;j++){
cin >> arr[j];

sort(arr,(arr)+ 4);
}
cout << "the Sorting array is " << arr << endl;
delete[] arr;
return 0;
}

/*************** *************** *************** *************** *************** ******/[/CODE]

[Laharl]

I have one question for you: If you're using <algorithm>, a) why not use sort() to do this for you and b) why not use the provided swap function, passing in a double pointer, if this is an academic excercise?

[DOOO]

I have one question for you: If you're using <algorithm>, a) why not use sort() to do this for you and b) why not use the provided swap function, passing in a double pointer, if this is an academic excercise?

yup it is a task i asked to do it

[Banfa]

I have an error in my cod which is trying to sort an arry using pointer i'd be grateful if any one help me to solve my problem and here is my code

What is the error, we can fix a problem if we don't know what the problem is!

One of the reasons your sorting algorithm is not working is that it is not a sorting algorithm, try looking up some sorting algorithms on Wikipedia.

[DOOO]

What is the error, we can fix a problem if we don't know what the problem is!

One of the reasons your sorting algorithm is not working is that it is not a sorting algorithm, try looking up some sorting algorithms on Wikipedia.

actually i have a quite good knowledge about sorting algorithms (merg,heap,bubb le ,...etc) but my program aimed to sort an array using pointer it is an application on pointer not on sorting algorithm and the problem is when i enter array to be sorted the program give me address in the memory . is it clear now?

[Banfa]

the problem is when i enter array to be sorted the program give me address in the memory . is it clear now?

Not really, your program contains no arrays. It contains a pointer you appear to be using a bit like an array but that is all.

Do you mean you are getting a SegFault/Memory Access Exception?

[DOOO]

[QUOTE=Banfa]Not really, your program contains no arrays. It contains a pointer you appear to be using a bit like an array but that is all.

Do you mean you are getting a SegFault/Memory Access Exception?[/QUO

DAMGE:after normal block (#45)at 0x00491d20

that is the error ,i can't understand it

[weaknessforcats]

Look at your sort.

You use begin+i+1. Assume a 5 element array and you are on the last element so i is 4. That makes begin+4+1, which is begin+5 and that is outside your array bounds.

[DOOO]

Look at your sort.

You use begin+i+1. Assume a 5 element array and you are on the last element so i is 4. That makes begin+4+1, which is begin+5 and that is outside your array bounds.

i am try to avoid this error but still have a problem

#include <list>
#include<iostream>
#include <algorithm>

using namespace std;

void sort(double* begin,double* end)

{  

for(int j=0;j<(end-begin)+1;j++)
{
 	for(int i=0;i<(end-begin)+1;i++)
	{
		if(*(begin+i)>*(end-i))
		{ 
	//	swap(*(begin+i),*(end-i));
			double temp = *(begin+i);
            *(begin+i) = *(end-i);
            *(end-i) = temp;

			

		}else {continue;}
	}
}	
}

int main()
{
double* arr = new double[6];

for(int j=0;j<6;j++){
cin >> arr[j];

sort(arr,(arr)+5);
}


//delete[] arr;
return 0;
}