range count

[Gary Wessle]

Hi
I have a vector<charwhic h looks like this (a d d d a d s g e d d d d
d k)
I need to get the biggest count of consecutive 'd'. 5 in this example

I am toying with this method but not sure if it is optimal.

thanks

int k = 0;
vector::const_i terator i = find(v.begin(), v.end(), 'r')
while ( i != v.end() ) {
vector::const_i terator j = find(i, v.end(), any_thing_but 'r')
if ( (j - i) k ) k = (j - i)
i = j
}

[Daniel T.]

In article <87************ @localhost.loca ldomain>,
Gary Wessle <ph****@yahoo.c omwrote:

Hi
I have a vector<charwhic h looks like this (a d d d a d s g e d d d d
d k)
I need to get the biggest count of consecutive 'd'. 5 in this example

I am toying with this method but not sure if it is optimal.

thanks

int k = 0;
vector::const_i terator i = find(v.begin(), v.end(), 'r')
while ( i != v.end() ) {
vector::const_i terator j = find(i, v.end(), any_thing_but 'r')
if ( (j - i) k ) k = (j - i)
i = j
}

I'll assume the 'r' was a typo. Shouldn't that last line be something
like "i = find( j, v.end(), 'r' );"?

This might be a useful time for for_each. (uncompiled, untested code)

struct count_consecuti ve: unary_function< char, void >
{
char comp;
unsigned count;
unsigned max_count;
count_same( char value )
: comp( value )
, count( 0 )
, max_count( 0 )
{ }
void operator()( char c ) {
if ( c == comp )
++count;
else {
max_count = max( count, max_count );
count = 0;
}
}

unsigned result() const { return max( count, max_count ); }
}

k = for_each( v.begin(), v.end(), count_consecuti ve( 'd' ) ).result();

The nice thing about the above is that it can be used in an initializer.

[Gary Wessle]

"Daniel T." <da******@earth link.netwrites:

In article <87************ @localhost.loca ldomain>,
Gary Wessle <ph****@yahoo.c omwrote:

Hi
I have a vector<charwhic h looks like this (a d d d a d s g e d d d d
d k)
I need to get the biggest count of consecutive 'd'. 5 in this example

I am toying with this method but not sure if it is optimal.

thanks

int k = 0;
vector::const_i terator i = find(v.begin(), v.end(), 'r')
while ( i != v.end() ) {
vector::const_i terator j = find(i, v.end(), any_thing_but 'r')
if ( (j - i) k ) k = (j - i)
i = j
}

I'll assume the 'r' was a typo. Shouldn't that last line be something
like "i = find( j, v.end(), 'r' );"?

This might be a useful time for for_each. (uncompiled, untested code)

struct count_consecuti ve: unary_function< char, void >
{
char comp;
unsigned count;
unsigned max_count;
count_same( char value )
: comp( value )
, count( 0 )
, max_count( 0 )
{ }
void operator()( char c ) {
if ( c == comp )
++count;
else {
max_count = max( count, max_count );
count = 0;
}
}

unsigned result() const { return max( count, max_count ); }
}

k = for_each( v.begin(), v.end(), count_consecuti ve( 'd' ) ).result();

The nice thing about the above is that it can be used in an initializer.

thank you for taking the time to post this, :) I am having hard time
understanding the code you gave because of my newbi status. I'd rather
write something I can grasp it for now till my level goes up.

here is my best shut

*************** * statistics.h *************** *
#ifndef STATISTICS_H
#define STATISTICS_H
#include <vector>
using std::vector;

#include <map>
using std::map;

class statistics
{
map<char, intmp;
vector<charv;
void stock_take();
int bigest_r(vector <charconst& cv);
bool not_r(char c);

public:
statistics(vect or<charconst& cv);
~statistics();
map<char,intget _counts;
};

#endif
*************** * statistics.cpp *************** *
#include <vector>
#include "statistics .h"

using namespace std;

statistics::sta tistics(vector< charconst& cv)
: v( cv )
{
statistics::sto ck_take();
}

void statistics::sto ck_take()
{
mp['c'] = count(v.begin() , v.end(), 'c');
mp['r'] = bigest_r(v);
}

bool statistics::not _r(char c)
{
return (c != 'r');
}

int statistics::big est_r(vector<ch arconst& cv)
{
int k = 0;
vector_iterator i = find(cv.begin() , v.end(), 'r');
while (i != cv.end()){
vector_iterator j = find_if(i, cv.end(), not_r);
if ( (j-i) k ) k = (j-i);
i = j;
}
return k;
}
};


*************** * statistics_test .cpp *************** *
#include <iostream>
using std::cout;

#include <vector>
using std::vector;

#include <utility>
using std::map;

#include "statistics .h"

int main() {

vector v = {c r r r d x c c d d d d k};
statistics st1(v);
cout << "c" << (st1.get_counts )[c]
<< "r" << (st1.get_counts )[r]
<< '\n';
}

[Daniel T.]

In article <87************ @localhost.loca ldomain>,
Gary Wessle <ph****@yahoo.c omwrote:

"Daniel T." <da******@earth link.netwrites:

This might be a useful time for for_each.

First, let me clean up what I wrote:

struct count_consecuti ve: unary_function< char, void >
{
char comp;
unsigned count;
unsigned max_count;

count_consecuti ve( char value )
: comp( value )
, count( 0 )
, max_count( 0 )
{ }

void operator()( char c ) {
if ( c == comp )
++count;
else {
max_count = max( count, max_count );
count = 0;
}
}

unsigned result() const { return max( count, max_count ); }
};

k = for_each( v.begin(), v.end(), count_consecuti ve( 'd' ) ).result();

thank you for taking the time to post this, :) I am having hard time
understanding the code you gave because of my newbi status. I'd rather
write something I can grasp it for now till my level goes up.

That's fine. Let's look at the algorithm you wrote:

int statistics::big est_r(vector<ch arconst& cv)
{
int k = 0;
vector_iterator i = find(cv.begin() , v.end(), 'r');
while (i != cv.end()){
vector_iterator j = find_if(i, cv.end(), not_r);
if ( (j-i) k ) k = (j-i);
i = j;
}
return k;
}

Obviously your code doesn't compile, but I'm going to ignore that for
now and look at your algorithm:

a r r r a r s g e r r r r r k

what will your algorithm do with the chars above?

find will return element 1 (the second element in the array,) then
find_if will return element 4.

4 - 1 0 so k is assigned 3.

Now i will be set to point at element 4, and we loop back up.

That's not the end of the vector, so find_if will set j to point at
element 4 (the first element that is not_r.)

4 - 4 3 is false, so loop back up (with i and j both pointing at
element 4 still.)

Your stuck in an infinite loop.

You see, "i" is the beginning of your streak of 'r's, and "j" is the end
of the streak, but then you assign "i" to the end of the first streak of
'r's and expect things to still work. At the end of your while block,
you need to reset "i" to the beginning of the next streak of 'r's (hint,
use "find" again.)

As to the syntax... You need to define the type of "vector_iterato r" and
"not_r" must be a global function, not a member function. (You could
make it a member function but it would be much more complicated and
pointless.

[Gary Wessle]

"Daniel T." <da******@earth link.netwrites:

In article <87************ @localhost.loca ldomain>,
Gary Wessle <ph****@yahoo.c omwrote:

"Daniel T." <da******@earth link.netwrites:

This might be a useful time for for_each.

First, let me clean up what I wrote:

struct count_consecuti ve: unary_function< char, void >
{
char comp;
unsigned count;
unsigned max_count;

count_consecuti ve( char value )
: comp( value )
, count( 0 )
, max_count( 0 )
{ }

void operator()( char c ) {
if ( c == comp )
++count;
else {
max_count = max( count, max_count );
count = 0;
}
}

unsigned result() const { return max( count, max_count ); }
};

k = for_each( v.begin(), v.end(), count_consecuti ve( 'd' ) ).result();

what is : unary_function< char, void after the struct name? and what
does it do?
can I replace the word struct with class and expect the same results?
I will stick with your code, mine is few steps behind.

[Gary Wessle]

"Daniel T." <da******@earth link.netwrites:

In article <87************ @localhost.loca ldomain>,
Gary Wessle <ph****@yahoo.c omwrote:

"Daniel T." <da******@earth link.netwrites:

This might be a useful time for for_each.

First, let me clean up what I wrote:

struct count_consecuti ve: unary_function< char, void >
{
char comp;
unsigned count;
unsigned max_count;

count_consecuti ve( char value )
: comp( value )
, count( 0 )
, max_count( 0 )
{ }

void operator()( char c ) {
if ( c == comp )
++count;
else {
max_count = max( count, max_count );
count = 0;
}
}

unsigned result() const { return max( count, max_count ); }
};

k = for_each( v.begin(), v.end(), count_consecuti ve( 'd' ) ).result();

thank you for taking the time to post this, :) I am having hard time
understanding the code you gave because of my newbi status. I'd rather
write something I can grasp it for now till my level goes up.

That's fine. Let's look at the algorithm you wrote:

int statistics::big est_r(vector<ch arconst& cv)
{
int k = 0;
vector_iterator i = find(cv.begin() , v.end(), 'r');
while (i != cv.end()){
vector_iterator j = find_if(i, cv.end(), not_r);
if ( (j-i) k ) k = (j-i);
i = j;
}
return k;
}

Obviously your code doesn't compile, but I'm going to ignore that for

I am embedding what you suggested in my code but would need some
direction, if you could please

*************** * statistics.h *************** *
#ifndef STATISTICS_H
#define STATISTICS_H
#include <vector>
using std::vector;

#include <map>
using std::map;

class count_consecuti ve: unary_function< char, void >
{
char comp;
unsigned count;
unsigned max_count;

public:
count_consecuti ve(char value);
~count_consecut ive();
void operator()(char c);
unsigned result();
};
class statistics
{
map<char, intmp;
vector<charv;
void stock_take();
int bigest_r(vector <charconst& cv);

public:
statistics(vect or<charconst& cv);
~statistics();
map<char,intget _counts;
};

#endif


*************** * statistics.cpp *************** *
#include <vector>
using std::vector;

#include <algorithm>
using std::count;

#include "statistics .h"
count_consecuti ve::count_conse cutive( char value )
: comp( value )
, count( 0 )
, max_count( 0 )
{ }

void count_consecuti ve::operator()( char c ) {
if ( c == comp )
++count;
else {
max_count = max( count, max_count );
count = 0;
}
}

unsigned count_consecuti ve::result() const {
return max( count, max_count );
}

statistics::sta tistics(vector< charconst& cv)
: v( cv )
{
statistics::sto ck_take();
}

void statistics::sto ck_take()
{
mp['c'] = count(v.begin() , v.end(), 'c');
mp['r'] = bigest_r(v);
}
int statistics::big est_r(vector<ch arconst& cv)
{
int k = for_each( cv.begin(), cv.end(),
count_consecuti ve( 'd' ) ).result();
return k;

}
*************** * statistics_test .cpp*********** *****
#include <iostream>
using std::cout;

#include <vector>
using std::vector;

#include "statistics .h"

int main() {

vector v = {c r r r d x c c d d d d k};
statistics st1(v);
cout << "c" << (st1.get_counts )[c]
<< "r" << (st1.get_counts )[r]
<< '\n';
}

[Rolf Magnus]

Gary Wessle wrote:

"Daniel T." <da******@earth link.netwrites:

>In article <87************ @localhost.loca ldomain>,
Gary Wessle <ph****@yahoo.c omwrote:

"Daniel T." <da******@earth link.netwrites:

This might be a useful time for for_each.

First, let me clean up what I wrote:

struct count_consecuti ve: unary_function< char, void >
{
char comp;
unsigned count;
unsigned max_count;

count_consecuti ve( char value )
: comp( value )
, count( 0 )
, max_count( 0 )
{ }

void operator()( char c ) {
if ( c == comp )
++count;
else {
max_count = max( count, max_count );
count = 0;
}
}

unsigned result() const { return max( count, max_count ); }
};

k = for_each( v.begin(), v.end(), count_consecuti ve( 'd' ) ).result();

what is : unary_function< char, void after the struct name?

The base type.

and what does it do?

Derive from it.

can I replace the word struct with class and expect the same results?

You'd have to make things explicitly public, e.g. by replacing the first 2
lines with:

class count_consecuti ve: public unary_function< char, void >
{
public:

I will stick with your code, mine is few steps behind.

[Daniel T.]

In article <87************ @localhost.loca ldomain>,
Gary Wessle <ph****@yahoo.c omwrote:

"Daniel T." <da******@earth link.netwrites:

In article <87************ @localhost.loca ldomain>,
Gary Wessle <ph****@yahoo.c omwrote:

"Daniel T." <da******@earth link.netwrites:
>
This might be a useful time for for_each.

First, let me clean up what I wrote:

struct count_consecuti ve: unary_function< char, void >
{
char comp;
unsigned count;
unsigned max_count;

count_consecuti ve( char value )
: comp( value )
, count( 0 )
, max_count( 0 )
{ }

void operator()( char c ) {
if ( c == comp )
++count;
else {
max_count = max( count, max_count );
count = 0;
}
}

unsigned result() const { return max( count, max_count ); }
};

k = for_each( v.begin(), v.end(), count_consecuti ve( 'd' ) ).result();

what is : unary_function< char, void after the struct name? and what
does it do?
can I replace the word struct with class and expect the same results?
I will stick with your code, mine is few steps behind.

It is defined in <functionalan d helps set up some typedefs. Strictly
speaking, it's not necessary for this example.

[Daniel T.]

In article <87************ @localhost.loca ldomain>,
Gary Wessle <ph****@yahoo.c omwrote:

"Daniel T." <da******@earth link.netwrites:

In article <87************ @localhost.loca ldomain>,
Gary Wessle <ph****@yahoo.c omwrote:

thank you for taking the time to post this, :) I am having hard time
understanding the code you gave because of my newbi status. I'd rather
write something I can grasp it for now till my level goes up.

That's fine. Let's look at the algorithm you wrote:

int statistics::big est_r(vector<ch arconst& cv)
{
int k = 0;
vector_iterator i = find(cv.begin() , v.end(), 'r');
while (i != cv.end()){
vector_iterator j = find_if(i, cv.end(), not_r);
if ( (j-i) k ) k = (j-i);
i = j;
}
return k;
}

Obviously your code doesn't compile, but I'm going to ignore that for

I am embedding what you suggested in my code but would need some
direction, if you could please.

What's the first error the compiler give you and what line does it point
to?

[Gary Wessle]

"Daniel T." <da******@earth link.netwrites:

In article <87************ @localhost.loca ldomain>,
Gary Wessle <ph****@yahoo.c omwrote:

"Daniel T." <da******@earth link.netwrites:

In article <87************ @localhost.loca ldomain>,
Gary Wessle <ph****@yahoo.c omwrote:
>
thank you for taking the time to post this, :) I am having hard time
understanding the code you gave because of my newbi status. I'd rather
write something I can grasp it for now till my level goes up.
>
That's fine. Let's look at the algorithm you wrote:
>
int statistics::big est_r(vector<ch arconst& cv)
{
int k = 0;
vector_iterator i = find(cv.begin() , v.end(), 'r');
while (i != cv.end()){
vector_iterator j = find_if(i, cv.end(), not_r);
if ( (j-i) k ) k = (j-i);
i = j;
}
return k;
}
>
Obviously your code doesn't compile, but I'm going to ignore that for

I am embedding what you suggested in my code but would need some
direction, if you could please.

What's the first error the compiler give you and what line does it point
to?

the code and the error are as listed ( thank you for helping :) )

*************** * statistics.h *************** *
#ifndef STATISTICS_H
#define STATISTICS_H
#include <vector>
using std::vector;

#include <map>
using std::map;

class count_consecuti ve : public unary_function< char, void >
{

public:

char comp;
unsigned count;
unsigned max_count;
count_consecuti ve(char value);
~count_consecut ive();
void operator()(char c);
unsigned result();
};
class statistics
{
map<char, intmp;
vector<charv;
void stock_take();
int bigest_r(vector <charconst& cv);

public:
statistics(vect or<charconst& cv);
~statistics();
map<char,intget _counts;
};

#endif
*************** * statistics.cpp *************** *
#include <vector>
using std::vector;

#include <algorithm>
using std::count;

#include "statistics .h"
count_consecuti ve::count_conse cutive( char value )
: comp( value )
, count( 0 )
, max_count( 0 )
{ }

void count_consecuti ve::operator()( char c ) {
if ( c == comp )
++count;
else {
max_count = max( count, max_count );
count = 0;
}
}

unsigned count_consecuti ve::result() const {
return max( count, max_count );
}

statistics::sta tistics(vector< charconst& cv)
: v( cv )
{
statistics::sto ck_take();
}

void statistics::sto ck_take()
{
mp['c'] = count(v.begin() , v.end(), 'c');
mp['r'] = bigest_r(v);
}
int statistics::big est_r(vector<ch arconst& cv)
{
int k = for_each( cv.begin(), cv.end(),
count_consecuti ve( 'd' ) ).result();
return k;

}

*************** * statistics_test .cpp *************** *
#include <iostream>
using std::cout;

#include <vector>
using std::vector;

#include "statistics .h"

int main() {

vector v = {c r r r d x c c d d d d k};
statistics st1(v);
cout << "c" << (st1.get_counts )[c]
<< "r" << (st1.get_counts )[r]
<< '\n';
}
*************** * error *************** *
$ make
g++ -c -o statistics.o statistics.cpp
statistics.h:9: error: expected template-name before '<' token
statistics.h:9: error: expected `{' before '<' token
statistics.h:9: error: expected unqualified-id before '<' token
statistics.cpp: 10: error: invalid use of undefined type 'class count_consecuti ve'
statistics.h:9: error: forward declaration of 'class count_consecuti ve'
statistics.cpp: In constructor 'count_consecut ive::count_cons ecutive(char)':
statistics.cpp: 11: error: class 'count_consecut ive' does not have any field named 'comp'
statistics.cpp: 12: error: class 'count_consecut ive' does not have any field named 'count'
statistics.cpp: 13: error: class 'count_consecut ive' does not have any field named 'max_count'
statistics.cpp: At global scope:
statistics.cpp: 16: error: invalid use of undefined type 'class count_consecuti ve'
statistics.h:9: error: forward declaration of 'class count_consecuti ve'
statistics.cpp: In member function 'void count_consecuti ve::operator()( char)':
statistics.cpp: 17: error: 'comp' was not declared in this scope
statistics.cpp: 18: error: no pre-increment operator for type
statistics.cpp: 20: error: 'max_count' was not declared in this scope
statistics.cpp: 20: error: 'max' was not declared in this scope
statistics.cpp: 21: error: overloaded function with no contextual type information
statistics.cpp: At global scope:
statistics.cpp: 25: error: invalid use of undefined type 'class count_consecuti ve'
statistics.h:9: error: forward declaration of 'class count_consecuti ve'
statistics.cpp: In member function 'unsigned int count_consecuti ve::result() const':
statistics.cpp: 26: error: 'max_count' was not declared in this scope
statistics.cpp: 26: error: 'max' was not declared in this scope
statistics.cpp: In member function 'int statistics::big est_r(const std::vector<cha r, std::allocator< char&)':
statistics.cpp: 47: error: invalid use of undefined type 'class count_consecuti ve'
statistics.h:9: error: forward declaration of 'class count_consecuti ve'
make: *** [statistics.o] Error 1
fred@debian:~/myPrograms/backtest$