post  funtion swap

olove05 (60)   Link to this post
somebory can tell me how to swap two colum of the two dimentional array that with pointer
Duoas (3472)   Link to this post
Use a loop.
It should iterate over the rows.
For each row, swap the two column values.
olove05 (60)   Link to this post
I did but do not work
I was in function swap
0 0x11 0
sh: pause: command not found
I was in destructor
*** glibc detected *** ./a.out: free(): invalid pointer: 0x0991d070 ***
======= Backtrace: =========
/lib/libc.so.6[0x5d5a68]
/lib/libc.so.6(__libc_free+0x78)[0x5d8f6f]
/usr/lib/libstdc++.so.6(_ZdlPv+0x21)[0xade801]
/usr/lib/libstdc++.so.6(_ZdaPv+0x1d)[0xade85d]
./a.out[0x8048e1d]
./a.out[0x8048efd]
/lib/libc.so.6(__libc_start_main+0xdc)[0x5874e4]
./a.out(__gxx_personality_v0+0x51)[0x8048791]
======= Memory map: ========
00555000-0056e000 r-xp 00000000 fd:00 1403592 /lib/ld-2.4.so
0056e000-0056f000 r-xp 00018000 fd:00 1403592 /lib/ld-2.4.so
0056f000-00570000 rwxp 00019000 fd:00 1403592 /lib/ld-2.4.so
00572000-0069f000 r-xp 00000000 fd:00 1403660 /lib/libc-2.4.so
0069f000-006a1000 r-xp 0012d000 fd:00 1403660 /lib/libc-2.4.so
006a1000-006a2000 rwxp 0012f000 fd:00 1403660 /lib/libc-2.4.so
Last edited on
Zhuge (629)   Link to this post
Looks like you are free()ing an invalid pointer. We would probably need to see code.
olove05 (60)   Link to this post
#include <iostream>
#include <string>


using namespace std;


/*TwoDimArray::TwoDimArray()
{
}
*/
TwoD::TwoD( int r, int c)
{

x = r;

y = c;

elemtD = new int *[x]; // **elemtD is a two Dim pointer in the private sector

for (int i = 0; i < x; i++){

elemtD[i] = new int [y];

}
for (int i=0; i < x; i++){

for(int j=0; j < y; j++){

elemtD[i][j] = i*j;
}
}
}

TwoD::TwoD(const TwoD & ap1) // copy constructor
{

deepCopy( ap1 );



}

TwoD::~TwoD( )
{



for (int i = 0; i < x; i++)
{
delete[] elemtD[i];

delete[] elemtD;

}
}

/*void TwoD::operator =( const TwoDimArray &right1 ) // overload assigment operator give run time error
{

if (this == &right1 )

return this;

delete elemtD;

deeCopy (right1);

return *this;

}
TwoD::~TwoD( )
{


for (int i = 0; i < x; i++)
{
delete[] elemtD[i];

delete[] elemtD;

}
}

/*void TwoD::operator =( const TwoD &right1 ) // overload assigment operator give run time error
{

if (this == &right1 )

return this;

delete elemtD;

deeCopy (right1);

return *this;

}
*/


/*void TwoD:: operator[](int i, int j);// give run time erros

{
return elemtwoDarray[i][j];

}
*/


void TwoD::deepCopy(const TwoD & orig1 )
{

x = orig1.x;

y = orig1.y;

elemtD= new int *[x]; // dynamically allocated array of int of set rows length

for (int i = 0; i < x; i++)
{
elemtD[i] = new int[x]; // Fill up row until x row
}

for ( int i = 0; i < x; i++ )
{
for ( int j = 0; j < y; j++ )
{
elemtD[i][j] = orig1.elemtD[i][j];

//elemtD[j] = orig2.elemtD[j];

}

}

}

int TwoD::print( int r , int c)
{

x= r

y=c;

for (int i = 0; i < x; i++)
{

for(int j=0; j < y; j++)
{

cout<<" " << elemtD[i][j] <<" ";
}

putchar('\n');

cout<<endl;
}
}



int TwoD::swap(int index1, int index2 )
{

x = index1;

y = index2;

int *temp;

for (int i = 0; i< x; i++)
{

temp = elemtD[y];

elemtD[ydim] = elemtD[x];

elemtD[x] = temp;

cout<<" " << elemtD[x]<<" ";

}
// putchar('\n');


cout<<endl;
}


-------------------------------------------------------------------
in main function


#include <iostream>
#include <string>
#include "numero3.h"

using namespace std;



int main()
{

TwoD TwD(3,4); // Declaring the three TwoD objects containing


cout << "\nElement values in the 2D Array are:\n";



TwD.print( 3,4 ); // Creating the arrays

TwD.deepCopy(TwD);// I have a question. If I have this function in the private section how I can call it in main?

cout << "\n The Swap element values in the 2D Array are:\n";


TwD.swap( 3,4 );



system("pause");

return 0;

};
olove05 (60)   Link to this post
Hello, no answer to this topic or any clue
guestgulkan (1277)   Link to this post
Well to get you started:

1. The assignment operator return type should be a reference NOT void.

2. In the assignment operator function - your delete code should be the same way it is done in the destructor.



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void TwoD::operator =( const TwoD &right1 ) // error - return type is NOT void
{

if (this == &right1 )

return this;

delete elemtD; //bad  deletion. It should be done like in the destructor

deeCopy (right1);

return *this;

}
olove05 (60)   Link to this post
thanks a lot
guestgulkan (1277)   Link to this post
While I'm thinking about it - the actual delete in the destructor is not quite right:

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TwoD::~TwoD( )
{

    for (int i = 0; i < x; i++)
   {
        delete[] elemtD[i];
       //delete[] elemtD;  //This should not  be in the loop
    }

   delete[] elemtD;  //It should be here

}



There appear to be another big issue in that some functions that would not be expected to
change the object (for example the print function) actually does change the object ( the x andy y values). That can't be good.
Last edited on
olove05 (60)   Link to this post
why my function just change the rows I want to change the columns


0 0 0 0 | 0 2 3 4
0 1 2 2 | 0 1 2 2
0 2 3 4 | 0 0 0 0
after swap we have (0,2)

wants

0 0 0 0
2 1 2 0
4 2 3 0

some clue that I can use to have the result that I want?
Last edited on
olove05 (60)   Link to this post
any clue guys?

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