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:

"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 :) )

OK, the first 3 errors:

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

We can see that it deals with the file "statistics .h" at line 9. So
let's look at that line:

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

Now, all three of the errors have a problem with what is just before the
'<' token so what is that? It's "unary_function ". How can the compiler
have a problem with that, it's part of the standard library? Well, first
as part of the standard library it's in the std namespace. Also it's
defined in a file that might not have been included (it's defined in
<functional>. )

So, fix that and compile again.

[Mark P]

Gary Wessle wrote:

>

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
}

How about the following?

int count_consecuti ve (const vector<char>& v, char c)
{
int current_count = 0;
int best_count = 0;
for (vector<char>:: const_iterator it = v.begin(); it != v.end(); ++it)
if (*it == c)
best_count = max(best_count, ++current_count );
else
current_count = 0;
return best_count;
}

Mark

[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:
>
"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 :) )

OK, the first 3 errors:

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

We can see that it deals with the file "statistics .h" at line 9. So
let's look at that line:

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

Now, all three of the errors have a problem with what is just before the
'<' token so what is that? It's "unary_function ". How can the compiler
have a problem with that, it's part of the standard library? Well, first
as part of the standard library it's in the std namespace. Also it's
defined in a file that might not have been included (it's defined in
<functional>. )

So, fix that and compile again.

thank you

I added
#include <functional>
using std::unary_func tion;
to the statistics.h

similarly I added to statistics.cpp
using std::max

so that it shows like
#include <algorithm>
using std::count;
using std::max

the error now are
*************** * error *************** *
t$ make clean; make
rm -rf *.o proj
g++ -c -o statistics.o statistics.cpp
statistics.h:4: error: expected `;' before 'using'
statistics.cpp: 29: error: prototype for 'unsigned int count_consecuti ve::result() const' does not match any in class 'count_consecut ive'
statistics.h:23 : error: candidate is: unsigned int count_consecuti ve::result()
make: *** [statistics.o] Error 1

here are the related sections of those files again
*************** * statistics.h *************** *
#ifndef STATISTICS_H
#define STATISTICS_H
#include <vector>
using std::vector; << --- line 4 I don't see a problem.

#include <functional>
using std::unary_func tion;

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

#include <algorithm>
using std::count;

#include <algorithm>
using std::max
#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 );
} << ------------- here is line 29, I really don't know what type max returns

on linux
$man::max returns nothing
The C++ Programming Language by Stroustrup did not have a easy-find
way in the index.
could you recommend a good ref. book and/or web link?

thanks

[Gary Wessle]

Mark P <us****@fall200 5REMOVE.fastmai lCAPS.fmwrites:

Gary Wessle wrote:

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
}

How about the following?

int count_consecuti ve (const vector<char>& v, char c)
{
int current_count = 0;
int best_count = 0;
for (vector<char>:: const_iterator it = v.begin(); it != v.end(); ++it)
if (*it == c)
best_count = max(best_count, ++current_count );

brilliant

else
current_count = 0;
return best_count;
}

Mark

thanks, I simplified the code a lot because of your good idea but I am
getting

ps. I am still working out the other sub-thread in the hope I will
learn something.

*************** * error *************** *
$ make clean; make
rm -rf *.o proj
g++ -c -o statistics.o statistics.cpp
statistics.h:4: error: expected `;' before 'using'
make: *** [statistics.o] Error 1
here is the code
*************** * 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();

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

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

#include <algorithm>
using std::max

#include "statistics .h"

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

void statistics::sto ck_take()
{
char r = 'r';
char c = 'c';
int current_count = 0;
int best_count = 0;
for (vector<char>:: const_iterator it = v.begin(); it != v.end(); ++it)
if (*it == r)
best_count = max(best_count, ++current_count );
else
if (*it != r){
current_count = 0;
if (*it == c)
mp[c]++ ;
}
mp[r] = best_count;
}
map<char,intsta tistics::get_co unts(){
return mp;
}

*************** * 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';
}

[Daniel T.]

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

the error now are
*************** * error *************** *
t$ make clean; make
rm -rf *.o proj
g++ -c -o statistics.o statistics.cpp
statistics.h:4: error: expected `;' before 'using'
statistics.cpp: 29: error: prototype for 'unsigned int
count_consecuti ve::result() const' does not match any in class
'count_consecut ive'
statistics.h:23 : error: candidate is: unsigned int
count_consecuti ve::result()
make: *** [statistics.o] Error 1

here are the related sections of those files again
*************** * statistics.h *************** *
#ifndef STATISTICS_H
#define STATISTICS_H
#include <vector>
using std::vector; << --- line 4 I don't see a problem.

#include <functional>
using std::unary_func tion;

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

#include <algorithm>
using std::count;

#include <algorithm>
using std::max
#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 );
} << ------------- here is line 29, I really don't know what type max returns

on linux
$man::max returns nothing
The C++ Programming Language by Stroustrup did not have a easy-find
way in the index.
could you recommend a good ref. book and/or web link?

thanks

To understand the error at line four, you have to understand how the
#include mechanism works. What it does is replace the line where the
#include is with the contents of the file. It works just like a
copy/paste. Many times a syntax error in a program won't be caught by
the compiler until it parses through a line or two more in the code. So,
if you don't see the problem in statistics.h look just above where it is
included. Remember, the compiler was looking for a ';' before the
'using'...

Fix that, post the code and the next error and we will continue. This
really is how I do it by the way, fix the first error then recompile.

[Gary Wessle]

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

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

the error now are
*************** * error *************** *
t$ make clean; make
rm -rf *.o proj
g++ -c -o statistics.o statistics.cpp
statistics.h:4: error: expected `;' before 'using'
statistics.cpp: 29: error: prototype for 'unsigned int
count_consecuti ve::result() const' does not match any in class
'count_consecut ive'
statistics.h:23 : error: candidate is: unsigned int
count_consecuti ve::result()
make: *** [statistics.o] Error 1

here are the related sections of those files again
*************** * statistics.h *************** *
#ifndef STATISTICS_H
#define STATISTICS_H
#include <vector>
using std::vector; << --- line 4 I don't see a problem.

#include <functional>
using std::unary_func tion;

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

#include <algorithm>
using std::count;

#include <algorithm>
using std::max
#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 );
} << ------------- here is line 29, I really don't know what type max returns

on linux
$man::max returns nothing
The C++ Programming Language by Stroustrup did not have a easy-find
way in the index.
could you recommend a good ref. book and/or web link?

thanks

To understand the error at line four, you have to understand how the
#include mechanism works. What it does is replace the line where the
#include is with the contents of the file. It works just like a
copy/paste. Many times a syntax error in a program won't be caught by
the compiler until it parses through a line or two more in the code. So,
if you don't see the problem in statistics.h look just above where it is
included. Remember, the compiler was looking for a ';' before the
'using'...

ahha
no ";" after max in statistics.cpp
using std::max

>
Fix that, post the code and the next error and we will continue. This
really is how I do it by the way, fix the first error then recompile.

ok, I fixed this, and compiled, I changed the name of the files where
the word statistics appears to statistics2

*************** * statistics2.h *************** *
#ifndef STATISTICS2_H
#define STATISTICS2_H
#include <vector>
using std::vector;

#include <functional>
using std::unary_func tion;

#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

*************** * statistics2.cpp *************** *
#include <vector>
using std::vector;

#include <algorithm>
using std::count;
using std::max;
#include "statistics 2.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() {
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;

}

*************** * statistics2_tes t.cpp *************** *
#include <iostream>
using std::cout;

#include <vector>
using std::vector;

#include <map>
using std::map;

#include "statistics 2.h"

int main() {

vector<charv = {c r r r d x c c d d d d k};
statistics st1(v);
map<char, intmci = st1.get_counts( );
cout << "c" << mci['c']
<< "r" << mci['r']
<< '\n';
}
*************** * error *************** *
$ make clean; make
rm -rf *.o proj
g++ -c -o statistics2.o statistics2.cpp
g++ -c -o statistics_test 2.o statistics_test 2.cpp
statistics_test 2.cpp: In function 'int main()':
statistics_test 2.cpp:14: error: 'c' was not declared in this scope
statistics_test 2.cpp:14: error: expected `}' before 'r'
statistics_test 2.cpp:14: error: 'v' must be initialized by constructor, not by '{...}'
statistics_test 2.cpp:14: error: expected ',' or ';' before 'r'
statistics_test 2.cpp: At global scope:
statistics_test 2.cpp:15: error: 'v' was not declared in this scope
statistics_test 2.cpp:16: error: no match for call to '(std::map<char , int, std::less<char> , std::allocator< std::pair<const char, int >) ()'
statistics_test 2.cpp:17: error: expected constructor, destructor, or type conversion before '<<' token
statistics_test 2.cpp:20: error: expected declaration before '}' token
make: *** [statistics_test 2.o] Error 1
fred@debian:~/myPrograms/backtest/res$

[Gary Wessle]

ok, if fixed them all, now it compiles, man what a learning
experience "many thanks to you".

the code does not give me what I want, but I will keep working on
that.

*************** * statistics2.h *************** *
#ifndef STATISTICS2_H
#define STATISTICS2_H
#include <vector>
using std::vector;

#include <functional>
using std::unary_func tion;

#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


*************** * statistics2.cpp *************** *
#include <vector>
using std::vector;

#include <algorithm>
using std::count;
using std::max;
#include "statistics 2.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() {
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;

}
map<char,intsta tistics::get_co unts(){
return mp;
}
*************** * statistics2_tes t.cpp *************** *
#include <iostream>
using std::cout;

#include <vector>
using std::vector;

#include <map>
using std::map;

#include "statistics 2.h"

int main() {

vector<charv;
v.push_back('c' );
v.push_back('r' );
v.push_back('r' );
v.push_back('c' );
v.push_back('r' );
v.push_back('r' );
v.push_back('r' );
v.push_back('r' );
statistics st1(v);
map<char, intmci = st1.get_counts( );
cout << "c" << mci['c']
<< "r" << mci['r']
<< '\n';
}
*************** * out put *************** *
c2r0

*************** * expected *************** *
c2r4

[Gary Wessle]

Mark P <us****@fall200 5REMOVE.fastmai lCAPS.fmwrites:

Gary Wessle wrote:

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
}

How about the following?

int count_consecuti ve (const vector<char>& v, char c)
{
int current_count = 0;
int best_count = 0;
for (vector<char>:: const_iterator it = v.begin(); it != v.end(); ++it)
if (*it == c)
best_count = max(best_count, ++current_count );
else
current_count = 0;
return best_count;
}

Mark

many thanks, here is the code after all the repairs

*************** * 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();

public:
statistics(vect or<charconst& cv);
~statistics(){}

map<char,intget _counts();
};

#endif

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

#include <algorithm>
using std::max;

#include "statistics .h"

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

void statistics::sto ck_take()
{
char r = 'r';
char c = 'c';
int current_count = 0;
int best_count = 0;
for (vector<char>:: const_iterator it = v.begin(); it != v.end(); ++it)
if (*it == r)
best_count = max(best_count, ++current_count );
else
if (*it != r){
current_count = 0;
if (*it == c)
mp[c]++ ;
}
mp[r] = best_count;
}
map<char,intsta tistics::get_co unts(){
return mp;
}

*************** * statistics_test .cpp *************** *

#include <iostream>
using std::cout;

#include <vector>
using std::vector;

#include <map>
using std::map;

#include "statistics .h"

int main() {
vector<charv;
v.push_back('c' );
v.push_back('r' );
v.push_back('r' );
v.push_back('c' );
v.push_back('r' );
v.push_back('r' );
v.push_back('r' );
v.push_back('r' );
statistics st1(v);
map<char, intmci = st1.get_counts( );
cout << "c" << mci['c']
<< "r" << mci['r']
<< '\n';
}

*************** * output *************** *
c2r4

[Daniel T.]

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

ok, if fixed them all, now it compiles, man what a learning
experience "many thanks to you".

the code does not give me what I want, but I will keep working on
that.

When you first posted about your problem, you seemed to be confused as
to whether you are trying to count the number of consecutive 'd's or the
number of consecutive 'r's. Your current code reflects that confusion.

Look at the function bigest_r. What are you trying to count?

[bjarne]

Gary Wessle wrote:

on linux
$man::max returns nothing
The C++ Programming Language by Stroustrup did not have a easy-find
way in the index.

Hmmm. Looked for max in the index, found max(), followed the first
reference to page 544 and found:

18.9 Min and Max
The algorithms described here select a value based on a comparison.
It is obviously useful to be
able to find the maximum and minimum of two values:

template<class T const T& max (const T& a , const T& b )
{
return (a <b ) ? b : a ;
}

Is that really too difficult?

could you recommend a good ref. book and/or web link?

thanks