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2010-05-25T14:21:17Z

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2010-05-25T10:29:07Z

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==Declare a reverse iterator to the vector of char==

<source lang="cpp">#include <iostream>
#include <vector>
using namespace std;
void show(const char *msg, vector<char> vect);
int main() {
vector<char> v;
// Declare an iterator to a vector<char>.
vector<char>::iterator itr;
// Obtain an iterator to the start of v.
itr = v.begin();
// Insert characters into v. An iterator to the inserted object is returned.
itr = v.insert(itr, "A");
itr = v.insert(itr, "B");
v.insert(itr, "C");
// Display the contents of v.
show("The contents of v: ", v);
// Declare a reverse iterator.
vector<char>::reverse_iterator ritr;
// Use a reverse iterator to show the contents of v in reverse.
cout << "Here is v in reverse: ";
for(ritr = v.rbegin(); ritr != v.rend(); ++ritr)
cout << *ritr << " ";
cout << "\n\n";
return 0;
}
void show(const char *msg, vector<char> vect) {
vector<char>::iterator itr;
cout << msg << endl;
for(itr=vect.begin(); itr != vect.end(); ++itr)
cout << *itr << endl;
}</source>

==Illustrating normal and reverse iteration.==

<source lang="cpp">#include <iostream>
#include <vector>
#include <list>
using namespace std;
int main()
{
cout << "Normal and reverse iteration through a vector:\n";
vector<int> vector1;
vector1.push_back(2);
vector1.push_back(3);
vector1.push_back(5);
vector1.push_back(7);
vector1.push_back(11);
cout << "Elements in normal (forward) order: ";
vector<int>::iterator i;
for (i = vector1.begin(); i != vector1.end(); ++i)
cout << *i << " ";
cout << endl;
cout << "Elements in reverse order: ";
vector<int>::reverse_iterator r;
for (r = vector1.rbegin(); r != vector1.rend(); ++r)
cout << *r << " ";
cout << endl;

cout << "Normal and reverse iteration through a list:\n";
list<int> list1(vector1.begin(), vector1.end());
cout << "Elements in normal (forward) order: ";
for (i = vector1.begin(); i != vector1.end(); ++i)
cout << *i << " ";
cout << endl;
cout << "Elements in reverse order: ";
for (r = vector1.rbegin(); r != vector1.rend(); ++r)
cout << *r << " ";
cout << endl;
return 0;
}</source>
<pre class=codeResult>Normal and reverse iteration through a vector:
Elements in normal (forward) order: 2 3 5 7 11
Elements in reverse order: 11 7 5 3 2
Normal and reverse iteration through a list:
Elements in normal (forward) order: 2 3 5 7 11
Elements in reverse order: 11 7 5 3 2</pre>

==Traverse reverse backward==

<source lang="cpp">#include <vector>
#include <iostream>
using namespace std;
vector<double> makevector(int size){
vector<double> result;
for (int i=1; i<=size; i++) {
result.push_back(double(i));
}
return result;
}
void print(const vector<double>& l)
{
cout << "Size of vector is: " << l.size() << endl;
vector<double>::const_iterator i;
for (i=l.begin(); i!=l.end(); i++)
{
cout << (*i) << " ";
}
cout << endl;
}
int main()
{
vector<double> vector1=makevector(5);
vector<double>::iterator bi;
bi=vector1.begin(); // Set iterator
while (bi!=vector1.end()) cout << (*bi++) << " ";
// Traverse backward
bi=(vector1.end());
do {
cout << (*--bi) << " ";
}
while (bi!=vector1.begin());
cout << endl << endl;
bi=vector1.begin();
cout << *bi << " "; // First element
cout << *(bi+=3) << " "; // 1+3 is 4th element
cout << *(bi-=1) << " "; // 4-1 is third element
cout << bi[-1] << " "; // 3-1 is second element
cout << bi[1] << endl << endl; // 3+1 is fourth element
}</source>

==Traverse reverse randomly==

<source lang="cpp">#include <vector>
#include <iostream>
using namespace std;
vector<double> makevector(int size){
vector<double> result;
for (int i=1; i<=size; i++) {
result.push_back(double(i));
}
return result;
}
void print(const vector<double>& l)
{
cout << "Size of vector is: " << l.size() << endl;
vector<double>::const_iterator i;
for (i=l.begin(); i!=l.end(); i++)
{
cout << (*i) << " ";
}
cout << endl;
}
int main()
{
vector<double> vector1=makevector(5);
vector<double>::iterator bi;
vector<double>::reverse_iterator ri;
ri=vector1.rbegin(); // Set iterator
while (ri!=vector1.rend()) cout << (*ri++) << " ";
cout << endl << endl;
// Traverse reverse backward
cout << "Traverse reverse backward" << endl;
ri=(vector1.rend());
do
{
cout << (*--ri) << " ";
}
while (ri!=vector1.rbegin());
cout << endl << endl;
}</source>

==Use a reverse iterator to show the contents of v in reverse==

<source lang="cpp">#include <iostream>
#include <vector>
using namespace std;
void show(const char *msg, vector<char> vect);
int main() {
vector<char> v;
// Declare an iterator to a vector<char>.
vector<char>::iterator itr;
// Obtain an iterator to the start of v.
itr = v.begin();
// Insert characters into v. An iterator to the inserted object is returned.
itr = v.insert(itr, "A");
itr = v.insert(itr, "B");
v.insert(itr, "C");
// Display the contents of v.
show("The contents of v: ", v);
// Declare a reverse iterator.
vector<char>::reverse_iterator ritr;
// Use a reverse iterator to show the contents of v in reverse.
cout << "Here is v in reverse: ";
for(ritr = v.rbegin(); ritr != v.rend(); ++ritr)
cout << *ritr << " ";
cout << "\n\n";
return 0;
}
void show(const char *msg, vector<char> vect) {
vector<char>::iterator itr;
cout << msg << endl;
for(itr=vect.begin(); itr != vect.end(); ++itr)
cout << *itr << endl;
}</source>

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