sort array of struct

**ravinder thakur** · Oct 9 '07, 02:35 PM

Re: sort array of struct

On Oct 9, 7:04 pm, tienlx <tien...@gmail. comwrote:

Hi all,
>
I want to sort an array of struct _line:
>
...
typedef struct _line
{
int x1;
int x2;} line;
>
bool comp(line l1,line l2)
{
if (l1.x1==l2.x1) return (l1.x2 < l2.x2);
return (l1.x1 < l2.x1);
>
}
>
line* R;
...
R = new line[k];
...
sort(&R[0],&R[k],comp);
...
delete[] R;
>
And when i printed out the array R, the result is wrong, but i run
well when i use vector<line>. And i don't know why sometimes the
program crashes when i use delete[] R; .Remove this line, it doesn't.
I use DevC++ 5, Win Vista.
>
Thanks for help,
tl

can you please paste what input (a small one) you are giving and what
output you are expecting ? your comparator function might be doing the
tricks.

**tienlx** · Oct 9 '07, 04:55 PM

Re: sort array of struct

Thanks for your reply,
I used a loop to print out the array:
for(int i=0;i<k;i++)
{
printf("%d ,%d\n",(R[i]).x1,(R[i]).x2);
}

Here is my output:
3094712 ,3084072
541872467 ,1987208531
544039282 ,1701603654
544039282 ,1701603654
544499311 ,1970497878
809000050 ,1869567068
842231141 ,1547322171
962359909 ,1413766192
977484654 ,1986348124
995913326 ,1348221507
.....

and what i want is
1,1
1,2
1,3
1,4
....
1,10
2,1
2,2
2,3
....
2,10
....
10,10

As you see, my input was in range 1-10,1-10 and i have no idea why
the result genenates random numbers.
Also, why the program crashes when i put this line in the end of
function to release the memory of array R:
delete[] R;
if i remove that line, i doesn't crash.

thanks,
tl

On Oct 9, 9:28 pm, ravinder thakur <ravindertha... @gmail.comwrote :

On Oct 9, 7:04 pm, tienlx <tien...@gmail. comwrote:
>
>
>

Hi all,

>

I want to sort an array of struct _line:

>

...
typedef struct _line
{
int x1;
int x2;} line;

>

bool comp(line l1,line l2)
{
if (l1.x1==l2.x1) return (l1.x2 < l2.x2);
return (l1.x1 < l2.x1);

>

}

>

line* R;
...
R = new line[k];
...
sort(&R[0],&R[k],comp);
...
delete[] R;

>

And when i printed out the array R, the result is wrong, but i run
well when i use vector<line>. And i don't know why sometimes the
program crashes when i use delete[] R; .Remove this line, it doesn't.
I use DevC++ 5, Win Vista.

>

Thanks for help,
tl

>
can you please paste what input (a small one) you are giving and what
output you are expecting ? your comparator function might be doing the
tricks.

**Jim Langston** · Oct 10 '07, 07:25 AM

Re: sort array of struct

"tienlx" <tienlex@gmail. comwrote in message
news:1191948309 .296192.298090@ g4g2000hsf.goog legroups.com...

Thanks for your reply,
I used a loop to print out the array:
for(int i=0;i<k;i++)
{
printf("%d ,%d\n",(R[i]).x1,(R[i]).x2);
}
>
Here is my output:
3094712 ,3084072
541872467 ,1987208531
544039282 ,1701603654
544039282 ,1701603654
544499311 ,1970497878
809000050 ,1869567068
842231141 ,1547322171
962359909 ,1413766192
977484654 ,1986348124
995913326 ,1348221507
....
>
and what i want is
1,1
1,2
1,3
1,4
...
1,10
2,1
2,2
2,3
...
2,10
...
10,10
>
>
As you see, my input was in range 1-10,1-10 and i have no idea why
the result genenates random numbers.
Also, why the program crashes when i put this line in the end of
function to release the memory of array R:
delete[] R;
if i remove that line, i doesn't crash.
>
thanks,
tl
>
On Oct 9, 9:28 pm, ravinder thakur <ravindertha... @gmail.comwrote :

>On Oct 9, 7:04 pm, tienlx <tien...@gmail. comwrote:
>>
>>
>>

Hi all,

>>

I want to sort an array of struct _line:

>>

...
typedef struct _line
{
int x1;
int x2;} line;

>>

bool comp(line l1,line l2)
{
if (l1.x1==l2.x1) return (l1.x2 < l2.x2);
return (l1.x1 < l2.x1);

>>

}

>>

line* R;
...
R = new line[k];
...
sort(&R[0],&R[k],comp);
...
delete[] R;

>>

And when i printed out the array R, the result is wrong, but i run
well when i use vector<line>. And i don't know why sometimes the
program crashes when i use delete[] R; .Remove this line, it doesn't.
I use DevC++ 5, Win Vista.

>>

Thanks for help,
tl

>>
>can you please paste what input (a small one) you are giving and what
>output you are expecting ? your comparator function might be doing the
>tricks.

All I can tell you is that the following produces the expected output. I.E.
1,1
1,2
1,3
etc...

Paste your actual code that is producing the errornous output etc...

#include <iostream>
#include <algorithm>

typedef struct _line
{
int x1;
int x2;
} line;

bool comp(line l1,line l2)
{
if (l1.x1==l2.x1) return (l1.x2 < l2.x2);
return (l1.x1 < l2.x1);
}

int main()
{
line* R;

int row = 10;
int col = 10;
int k = row * col;

R = new line[k];
int count = 0;
for ( int i = 10; i 0; --i )
{
for ( int j = 10; j 0; --j )
{
R[count].x1 = i;
R[count].x2 = j;
count++;
if ( count k )
{
std::cout << "Overflowed the buffer, dummy!\n";
return 0;
}

}
}

std::sort(&R[0],&R[k],comp);

for(int i=0;i<k;i++)
{
printf("%d ,%d\n",(R[i]).x1,(R[i]).x2);
}

delete[] R;

}

**terminator** · Oct 10 '07, 12:25 PM

Re: sort array of struct

On Oct 10, 10:16 am, "Jim Langston" <tazmas...@rock etmail.comwrote :

"tienlx" <tien...@gmail. comwrote in message
>
news:1191948309 .296192.298090@ g4g2000hsf.goog legroups.com...
>
>
>
>
>

Thanks for your reply,
I used a loop to print out the array:
for(int i=0;i<k;i++)
{
printf("%d ,%d\n",(R[i]).x1,(R[i]).x2);
}

>

Here is my output:
3094712 ,3084072
541872467 ,1987208531
544039282 ,1701603654
544039282 ,1701603654
544499311 ,1970497878
809000050 ,1869567068
842231141 ,1547322171
962359909 ,1413766192
977484654 ,1986348124
995913326 ,1348221507
....

>

and what i want is
1,1
1,2
1,3
1,4
...
1,10
2,1
2,2
2,3
...
2,10
...
10,10

>

As you see, my input was in range 1-10,1-10 and i have no idea why
the result genenates random numbers.
Also, why the program crashes when i put this line in the end of
function to release the memory of array R:
delete[] R;
if i remove that line, i doesn't crash.

>

thanks,
tl

>

On Oct 9, 9:28 pm, ravinder thakur <ravindertha... @gmail.comwrote :

On Oct 9, 7:04 pm, tienlx <tien...@gmail. comwrote:

>

Hi all,

>

I want to sort an array of struct _line:

>

...
typedef struct _line
{
int x1;
int x2;} line;

>

bool comp(line l1,line l2)
{
if (l1.x1==l2.x1) return (l1.x2 < l2.x2);
return (l1.x1 < l2.x1);

>

}

>

line* R;
...
R = new line[k];
...
sort(&R[0],&R[k],comp);
...
delete[] R;

>

And when i printed out the array R, the result is wrong, but i run
well when i use vector<line>. And i don't know why sometimes the
program crashes when i use delete[] R; .Remove this line, it doesn't.
I use DevC++ 5, Win Vista.

>

Thanks for help,
tl

>

can you please paste what input (a small one) you are giving and what
output you are expecting ? your comparator function might be doing the
tricks.

>
All I can tell you is that the following produces the expected output. I.E.
1,1
1,2
1,3
etc...
>
Paste your actual code that is producing the errornous output etc...
>
#include <iostream>
#include <algorithm>
>
typedef struct _line
{
int x1;
int x2;
>
} line;
>
bool comp(line l1,line l2)
{
if (l1.x1==l2.x1) return (l1.x2 < l2.x2);
return (l1.x1 < l2.x1);
>
}
>
int main()
{
line* R;
>
int row = 10;
int col = 10;
int k = row * col;
>
R = new line[k];
int count = 0;
for ( int i = 10; i 0; --i )
{
for ( int j = 10; j 0; --j )
{
R[count].x1 = i;
R[count].x2 = j;
count++;
if ( count k )
{
std::cout << "Overflowed the buffer, dummy!\n";
return 0;
}
>
}
}
>
std::sort(&R[0],&R[k],comp);
>
for(int i=0;i<k;i++)
{
printf("%d ,%d\n",(R[i]).x1,(R[i]).x2);
}
>
delete[] R;
>
>
>
}

I think the problem is that he 'print's after 'delete'.

printf("%d ,%d\n",(R[i]).x1,(R[i]).x2);

why not to use 'cout'?

#include <iostream>
using namespace std;
....
cout << R[i].x1 << ',' << (R[i].x2 <<'\n';

regards,
FM.

**Jim Langston** · Oct 10 '07, 08:35 PM

Re: sort array of struct

"terminator " <farid.mehrabi@ gmail.comwrote in message
news:1192018931 .306495.109520@ o3g2000hsb.goog legroups.com...

On Oct 10, 10:16 am, "Jim Langston" <tazmas...@rock etmail.comwrote :

>"tienlx" <tien...@gmail. comwrote in message
>>
>news:119194830 9.296192.298090 @g4g2000hsf.goo glegroups.com.. .
>>
>>
>>
>>
>>

Thanks for your reply,
I used a loop to print out the array:
for(int i=0;i<k;i++)
{
printf("%d ,%d\n",(R[i]).x1,(R[i]).x2);
}

>>

Here is my output:
3094712 ,3084072
541872467 ,1987208531
544039282 ,1701603654
544039282 ,1701603654
544499311 ,1970497878
809000050 ,1869567068
842231141 ,1547322171
962359909 ,1413766192
977484654 ,1986348124
995913326 ,1348221507
....

>>

and what i want is
1,1
1,2
1,3
1,4
...
1,10
2,1
2,2
2,3
...
2,10
...
10,10

>>

As you see, my input was in range 1-10,1-10 and i have no idea why
the result genenates random numbers.
Also, why the program crashes when i put this line in the end of
function to release the memory of array R:
delete[] R;
if i remove that line, i doesn't crash.

>>

thanks,
tl

>>

On Oct 9, 9:28 pm, ravinder thakur <ravindertha... @gmail.comwrote :
>On Oct 9, 7:04 pm, tienlx <tien...@gmail. comwrote:

>>

Hi all,

>>

I want to sort an array of struct _line:

>>

...
typedef struct _line
{
int x1;
int x2;} line;

>>

bool comp(line l1,line l2)
{
if (l1.x1==l2.x1) return (l1.x2 < l2.x2);
return (l1.x1 < l2.x1);

>>

}

>>

line* R;
...
R = new line[k];
...
sort(&R[0],&R[k],comp);
...
delete[] R;

>>

And when i printed out the array R, the result is wrong, but i run
well when i use vector<line>. And i don't know why sometimes the
program crashes when i use delete[] R; .Remove this line, it
doesn't.
I use DevC++ 5, Win Vista.

>>

Thanks for help,
tl

>>

>can you please paste what input (a small one) you are giving and what
>output you are expecting ? your comparator function might be doing the
>tricks.

>>
>All I can tell you is that the following produces the expected output.
>I.E.
>1,1
>1,2
>1,3
>etc...
>>
>Paste your actual code that is producing the errornous output etc...
>>
>#include <iostream>
>#include <algorithm>
>>
>typedef struct _line
>{
> int x1;
> int x2;
>>
>} line;
>>
>bool comp(line l1,line l2)
>{
> if (l1.x1==l2.x1) return (l1.x2 < l2.x2);
> return (l1.x1 < l2.x1);
>>
>}
>>
>int main()
>{
> line* R;
>>
> int row = 10;
> int col = 10;
> int k = row * col;
>>
> R = new line[k];
> int count = 0;
> for ( int i = 10; i 0; --i )
> {
> for ( int j = 10; j 0; --j )
> {
> R[count].x1 = i;
> R[count].x2 = j;
> count++;
> if ( count k )
> {
> std::cout << "Overflowed the buffer, dummy!\n";
> return 0;
> }
>>
> }
> }
>>
> std::sort(&R[0],&R[k],comp);
>>
> for(int i=0;i<k;i++)
> {
> printf("%d ,%d\n",(R[i]).x1,(R[i]).x2);
> }
>>
> delete[] R;
>>
>>
>>
>}

>
I think the problem is that he 'print's after 'delete'.
>

printf("%d ,%d\n",(R[i]).x1,(R[i]).x2);

why not to use 'cout'?
>
#include <iostream>
using namespace std;
...
cout << R[i].x1 << ',' << (R[i].x2 <<'\n';

Yes, when I orignally copied the code and did a quick program, I was
printfing after the delete[] and getting the same results at the OP. So I
moved the delete to the correct position. That may be possible.

And actually there are a few things I would change about this program, get
rid of the typedef (not needed in C++), std::cout instead of printf, etc..
but I left everything as the OP had it to show that the code he had shown
wasn't the issue.

sort array of struct

sort array of struct

Comment

Comment

Comment

Comment

Comment