erase-remove usage

[Wing]

Hello,

I have the following code:

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

class Obj
{
public:
int time;
string str;
};

vector<Objarray ;

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

I would like to remove all the "Obj" objects where their "time"
variables are less than or equal to, say x. Could anyone teach me how
to use erase-remove to do that?

Thank you so much!

[Ian Collins]

Re: erase-remove usage

Wing wrote:

Hello,
>
I have the following code:
>
////////////////////////////
>
class Obj
{
public:
int time;
string str;
};
>
vector<Objarray ;
>
////////////////////////
>
I would like to remove all the "Obj" objects where their "time"
variables are less than or equal to, say x. Could anyone teach me how
to use erase-remove to do that?
>

Read up on std::vector.rem ove_if(). a google for "vector remove_if"
will find you some examples.

--
Ian Collins.

[Wing]

Re: erase-remove usage

Hello,

I have googled for this topic. However, all the examples I saw are
based on vector<int>.

I think that I need to add some extra functions into my code in order
to do what I want. Anyone can give me some pointer? I am very
confused.... :(

Thank you.


Ian Collins wrote:

Wing wrote:

Hello,

I have the following code:

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

class Obj
{
public:
int time;
string str;
};

vector<Objarray ;

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

I would like to remove all the "Obj" objects where their "time"
variables are less than or equal to, say x. Could anyone teach me how
to use erase-remove to do that?

Read up on std::vector.rem ove_if(). a google for "vector remove_if"
will find you some examples.
>
--
Ian Collins.

[Ian Collins]

Re: erase-remove usage

Wing wrote:

Please don't top post.

Ian Collins wrote:
>

>>Wing wrote:
>>

>>>Hello,
>>>
>>>I have the following code:
>>>
>>>////////////////////////////
>>>
>>>class Obj
>>>{
>>>public:
>> int time;
>> string str;
>>>};
>>>
>>>vector<Objar ray;
>>>
>>>////////////////////////
>>>
>>>I would like to remove all the "Obj" objects where their "time"
>>>variables are less than or equal to, say x. Could anyone teach me how
>>>to use erase-remove to do that?
>>>

>>
>>Read up on std::vector.rem ove_if(). a google for "vector remove_if"
>>will find you some examples.
>>

Hello,
>
I have googled for this topic. However, all the examples I saw are
based on vector<int>.
>

Probably because it's the most straightforward case!

I think that I need to add some extra functions into my code in order
to do what I want. Anyone can give me some pointer? I am very
confused.... :(
>

Extending your Obj to give an example:

#include <vector>
#include <functional>
#include <string>
#include <iostream>
#include <algorithm>
#include <iterator>

struct Obj
{
int time;
std::string str;
Obj( int time ) : time(time) {}
friend std::ostream& operator<<( std::ostream& out, const Obj& o ){
return out << o.time;
}
};

struct RemoveAfter : std::unary_func tion<Obj, bool>
{
bool operator()(cons t Obj& x){ return x.time 10; }
};

int main() {
std::vector<Obj array;

array.push_back ( Obj( 5 ) );
array.push_back ( Obj( 15 ) );
array.push_back ( Obj( 10 ) );

std::copy(array .begin(),
array.end(),
std::ostream_it erator<Obj>(std ::cout," "));
std::cout << std::endl;

std::vector<Obj >::iterator last = std::remove_if( array.begin(),
array.end(),
RemoveAfter() );
std::copy(array .begin(),
last,
std::ostream_it erator<Obj>(std ::cout," "));
std::cout << std::endl;
}

--
Ian Collins.