в 14:21, 25 мая 2010

2010-05-25T14:21:06Z

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2010-05-25T10:27:45Z

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==Change contents of vector through an iterator==

<source lang="cpp">

#include <iostream>
#include <vector>
#include <cctype>
using namespace std;
int main()
{
vector<char> v(10); // create a vector of length 10
vector<char>::iterator p; // create an iterator
int i;
// assign elements in vector a value
p = v.begin();
i = 0;
while(p != v.end()) {
*p = i + "a";
p++;
i++;
}
// display contents of vector
cout << "Original contents:\n";
p = v.begin();
while(p != v.end()) {
cout << *p << " ";
p++;
}
cout << "\n\n";

// change contents of vector
p = v.begin();
while(p != v.end()) {
*p = toupper(*p);
p++;
}

// display contents of vector
cout << "Original contents:\n";
p = v.begin();
while(p != v.end()) {
cout << *p << " ";
p++;
}
cout << "\n\n";
return 0;
}
/*
Original contents:
a b c d e f g h i j
Original contents:
A B C D E F G H I J

*/

</source>

==const_iterator from different containers==

<source lang="cpp">
#include <algorithm>
#include <vector>
#include <list>
#include <iostream>
using namespace std;
int main ()
{
vector <int> v;
for (int nNum = -9; nNum < 10; ++ nNum)
v.push_back (nNum);
v.push_back (9);
v.push_back (9);
list <int> l;
for (int nNum = -4; nNum < 5; ++ nNum)
l.push_back (nNum);
vector <int>::const_iterator vi;
for ( vi = v.begin (); vi != v.end (); ++ vi )
cout << *vi << " ";
list <int>::const_iterator li;
for ( li = l.begin (); li != l.end (); ++ li )
cout << *li << " ";
return 0;
}

</source>

==Display contents of vector through an iterator==

<source lang="cpp">

#include <iostream>
#include <vector>
#include <cctype>
using namespace std;
int main()
{
vector<char> v(10); // create a vector of length 10
vector<char>::iterator p; // create an iterator
int i;
// assign elements in vector a value
p = v.begin();
i = 0;
while(p != v.end()) {
*p = i + "a";
p++;
i++;
}
// display contents of vector
cout << "Original contents:\n";
p = v.begin();
while(p != v.end()) {
cout << *p << " ";
p++;
}
cout << "\n\n";
return 0;
}
/*
Original contents:
a b c d e f g h i j

*/

</source>

==interator operator for vector==

<source lang="cpp">
#include <vector>
using namespace std;
int main(int argc, char** argv)
{
vector<int> intVector(10, 0);
vector<int>::iterator it = intVector.begin();
it += 5;
--it;
*it = 4;
return (0);
}

</source>

==Loop through all elements in a vector in reverse order by using rbegn, rend==

<source lang="cpp">

/* The following code example is taken from the book
* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* Permission to copy, use, modify, sell and distribute this software
* is granted provided this copyright notice appears in all copies.
* This software is provided "as is" without express or implied
* warranty, and with no claim as to its suitability for any purpose.
*/
#include <iostream>
#include <vector>
#include <algorithm>
#include <iterator>
using namespace std;
int main()
{
vector<int> coll;
// insert elements from 1 to 9
for (int i=1; i<=9; ++i) {
coll.push_back(i);
}
// print all element in reverse order
copy (coll.rbegin(), coll.rend(), // source
ostream_iterator<int>(cout," ")); // destination
cout << endl;
}
/*
9 8 7 6 5 4 3 2 1
*/

</source>

==Use const_iterator to loop through the vector==

<source lang="cpp">

#include <iostream>
using std::cout;
using std::endl;
#include <vector>
using std::vector;
int main()
{
int array[ 6 ] = { 1, 2, 3, 4, 5, 6 }; // initialize array
vector< int > integers; // create vector of ints
integers.push_back( 2 );
integers.push_back( 3 );
integers.push_back( 4 );
vector< int >::const_iterator constIterator;
// display vector elements using const_iterator
for ( constIterator = integers.begin();
constIterator != integers.end(); ++constIterator )
cout << *constIterator << " ";
cout << endl;
return 0;
}
/*
2 3 4
*/

</source>

==vector.begin, vector.end returns the iterators==

<source lang="cpp">
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main(void)
{
const int VECTOR_SIZE = 8 ;
typedef vector<int> IntVector ;
typedef IntVector::iterator IntVectorIt ;
IntVector Numbers(VECTOR_SIZE) ;
IntVectorIt start, end, it ;
Numbers[0] = 4;
Numbers[1] = 1;
Numbers[2] = 7;
Numbers[3] = 3;
Numbers[4] = 1;
Numbers[5] = 6;
Numbers[6] = 9;
Numbers[7] = 10;
start = Numbers.begin() ;
end = Numbers.end() ;
for(it = start; it != end; it++)
cout << *it << " " ;
random_shuffle(start, end) ;
for(it = start; it != end; it++)
cout << *it << " " ;
}

</source>

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