C++/Data Structure/Vector Utility — различия между версиями
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Версия 14:21, 25 мая 2010
Содержание
- 1 Another way to sort a sequence into descending order.
- 2 A vector may allocate more memory than it currently needs.
- 3 Demonstrate back_insert_iterator in vector
- 4 Demonstrate binary_search() in vector
- 5 Demonstrate count_if and not1 in vector
- 6 Demonstrate find() and find_if() in vector
- 7 Demonstrate front_insert_iterator in vector
- 8 Demonstrate insert_iterator in a vector
- 9 Demonstrate lower_bound() in vector
- 10 Demonstrate mismatch() in vector
- 11 Demonstrate random_shuffle() in vector
- 12 Demonstrate search() in vector
- 13 Demonstrating partial_sort() in vector
- 14 Demonstrating remove() and replace() in vector
- 15 Demonstrating sort() in vector
- 16 Demonstrating unique() in vector
- 17 Exchange elements from two different types of containers.
- 18 Find minimum and maximum inside a vector
- 19 Generating a sequence in vector
- 20 Insert one vector into another using an insert iterator
- 21 Merge two sequences
- 22 Right-rotate a sequence in vector
- 23 Rotate a sequence in vector
- 24 set_union, set_difference, set_symmetric_difference, set_intersection
- 25 Sorting a vector into descending order in vector
- 26 Transforming a sequence in vector
- 27 Use a function adaptor in vector
- 28 Use a unary function object to determine even/odd.
- 29 Use for_each() in vector
- 30 Use the logical_not unary function object in vector
- 31 Using copy() in Vector
- 32 Using swap_ranges() in Vector
Another way to sort a sequence into descending order.
#include <iostream>
#include <vector>
#include <algorithm>
#include <functional>
using namespace std;
int main()
{
vector<char> vectorObject(26);
int i;
for(i = 0; i <vectorObject.size(); i++)
vectorObject[ i ] = "A"+i;
cout << "Original ordering of vectorObject:";
for(i = 0; i <vectorObject.size(); i++)
cout << vectorObject[ i ] << " ";
cout << endl;
sort(vectorObject.begin(), vectorObject.end(), not2(less<char>())); // sort into desceding order
cout << "After sorting vectorObject using not2(less<char>()):";
for(i = 0; i <vectorObject.size(); i++)
cout << vectorObject[ i ] << " ";
return 0;
}
A vector may allocate more memory than it currently needs.
#include <iostream>
#include <vector>
using namespace std;
int main()
{
vector<char> vectorObject(10);
cout << "Initial size: " << vectorObject.size() << endl;
cout << "Initial capacity: " << vectorObject.capacity();
cout << "\n\n";
vectorObject.push_back("X");
cout << "Size after push_back: " << vectorObject.size() << endl;
cout << "New capacity: " << vectorObject.capacity();
cout << "\n\n";
vectorObject.resize(100);
cout << "Size after resize: " << vectorObject.size() << endl;
cout << "Capacity after resize: " << vectorObject.capacity();
cout << "\n\n";
vectorObject.push_back("Y");
cout << "Size after push_back: " << vectorObject.size() << endl;
cout << "New capacity: " << vectorObject.capacity();
cout << "\n\n";
return 0;
}
Demonstrate back_insert_iterator in vector
#include <iostream>
#include <iterator>
#include <vector>
using namespace std;
int main()
{
vector<int> vectorObject, vectorObject2;
vector<int>::iterator itr;
int i;
for(i = 0; i <5; i++)
vectorObject.push_back(i);
cout << "Original contents of vectorObject: ";
itr = vectorObject.begin();
while(itr != vectorObject.end())
cout << *itr++ << " ";
cout << endl;
back_insert_iterator<vector<int> > bck_i_itr(vectorObject); // create a back_insert_iterator to vectorObject
*bck_i_itr++ = 100; // insert rather than overwrite at end
*bck_i_itr = 200;
cout << "vectorObject after insertion: ";
itr = vectorObject.begin();
while(itr != vectorObject.end())
cout << *itr++ << " ";
cout << endl;
cout << "Size of vectorObject2 before copy: " << vectorObject2.size() << endl;
copy(vectorObject.begin(), vectorObject.end(), back_inserter(vectorObject2)); // copy vectorObject to vectorObject2 using back inserter
cout << "Size of vectorObject2 after copy: " << vectorObject2.size() << endl;
cout << "Contents of vectorObject2 after insertion: ";
itr = vectorObject2.begin();
while(itr != vectorObject2.end())
cout << *itr++ << " ";
return 0;
}
Demonstrate binary_search() in vector
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
vector<char> vectorObject;
bool result;
int i;
for(i = 0; i <10; i++)
vectorObject.push_back("A" + i);
cout << "Contents of vectorObject: ";
for(i = 0; i <vectorObject.size(); i++)
cout << vectorObject[ i ];
cout << endl;
cout << "Looking for F.";
result = binary_search(vectorObject.begin(), vectorObject.end(), "F");
if(result)
cout << "F Found";
else
cout << "F Not Found";
cout << "Looking for X.\n";
result = binary_search(vectorObject.begin(), vectorObject.end(), "X");
if(result)
cout << "X Found\n";
else
cout << "X Not Found\n";
return 0;
}
Demonstrate count_if and not1 in vector
#include <iostream>
#include <vector>
#include <functional>
#include <algorithm>
using namespace std;
int main()
{
vector<char> vectorObject;
int num;
int i;
for(i = 0; i <26; i++)
vectorObject.push_back(i+"A");
cout << "Sequence contains:";
for(i = 0; i <vectorObject.size(); i++)
cout << vectorObject[ i ] << " ";
cout << endl;
num = count_if(vectorObject.begin(), vectorObject.end(), bind2nd(greater<int>(), "r"));
cout << "There are " << num;
cout << " elements greater than E.\n";
num = count_if(vectorObject.begin(), vectorObject.end(), not1(bind2nd(greater<int>(), "r")));
cout << "There are " << num;
cout << " elements not greater than E.";
return 0;
}
Demonstrate find() and find_if() in vector
#include <iostream>
#include <vector>
#include <algorithm>
#include <cstring>
using namespace std;
bool iscomma(char ch) {
if(ch == ",")
return true;
return false;
}
int main()
{
vector<char> vectorObject;
vector<char>::iterator p;
char str[] = "One, Two, Three, Four, Five, Six";
int i;
for(i = 0; i < strlen(str); i++)
vectorObject.push_back(str[ i ]);
cout << "Contents of vectorObject: ";
for(i = 0; i < vectorObject.size(); i++)
cout << vectorObject[ i ];
cout << endl;
p = find(vectorObject.begin(), vectorObject.end(), "T"); // find the first T
cout << "Sequence beginning with T: ";
while(p != vectorObject.end())
cout << *p++;
cout << endl;
p = find_if(vectorObject.begin(), vectorObject.end(), iscomma); // find first comma
cout << "After find first comma: ";
while(p != vectorObject.end())
cout << *p++;
cout << endl;
return 0;
}
Demonstrate front_insert_iterator in vector
#include <iostream>
#include <iterator>
#include <list>
using namespace std;
int main()
{
list<int> vectorObject, vectorObject2;
list<int>::iterator itr;
int i;
for(i = 0; i <5; i++)
vectorObject.push_back(i);
cout << "Original contents of vectorObject: ";
itr = vectorObject.begin();
while(itr != vectorObject.end())
cout << *itr++ << " ";
cout << endl;
front_insert_iterator<list<int> > frnt_i_itr(vectorObject); // create a front_insert_iterator to vectorObject
*frnt_i_itr++ = 100; // insert rather than overwrite at front
*frnt_i_itr = 200;
cout << "vectorObject after insertion: ";
itr = vectorObject.begin();
while(itr != vectorObject.end())
cout << *itr++ << " ";
cout << endl;
cout << "Size of vectorObject2 before copy: " << vectorObject2.size() << endl;
copy(vectorObject.begin(), vectorObject.end(), front_inserter(vectorObject2));
cout << "Size of vectorObject2 after copy: " << vectorObject2.size() << endl;
cout << "Contents of vectorObject2 after insertion: ";
itr = vectorObject2.begin();
while(itr != vectorObject2.end())
cout << *itr++ << " ";
return 0;
}
Demonstrate insert_iterator in a vector
#include <iostream>
#include <iterator>
#include <vector>
using namespace std;
int main()
{
vector<int> vectorObject;
vector<int>::iterator itr;
int i;
for(i = 0; i <5; i++)
vectorObject.push_back( i );
cout << "Original contents of vectorObject: ";
itr = vectorObject.begin();
while(itr != vectorObject.end())
cout << *itr++ << " ";
cout << endl;
itr = vectorObject.begin();
itr += 2; // point to element 2
insert_iterator<vector<int> > i_itr(vectorObject, itr); // create insert_iterator to element 2
*i_itr++ = 100; // insert rather than overwrite
*i_itr = 200;
cout << "vectorObject after insertion: ";
itr = vectorObject.begin();
while(itr != vectorObject.end())
cout << *itr++ << " ";
return 0;
}
Demonstrate lower_bound() in vector
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
vector<char> vectorObject;
vector<char>::iterator p;
int i;
for(i = 0; i <10; i++)
vectorObject.push_back("A" + i);
cout << "Contents of vectorObject: ";
for(i = 0; i <vectorObject.size(); i++)
cout << vectorObject[ i ];
cout << endl;
cout << "Looking for F...";
p = lower_bound(vectorObject.begin(), vectorObject.end(), "F");
if(p != vectorObject.end())
cout << *p << " Found";
else
cout << "F Not Found";
cout << "\n Looking for X.";
p = lower_bound(vectorObject.begin(), vectorObject.end(), "X");
if(p != vectorObject.end())
cout << *p << " Found";
else
cout << "X Not Found";
return 0;
}
Demonstrate mismatch() in vector
#include <iostream>
#include <vector>
#include <algorithm>
#include <cstring>
#include <utility>
using namespace std;
int main()
{
vector<char> vectorObject, vectorObject2;
pair<vector<char>::iterator, vector<char>::iterator> p;
char str1[] = "O, T, T, T";
char str2[] = "O, T, F, F, N";
int i;
for(i = 0; i <strlen(str1); i++)
vectorObject.push_back(str1[ i ]);
for(i = 0; i <strlen(str2); i++)
vectorObject2.push_back(str2[ i ]);
cout << "Contents of vectorObject: ";
for(i = 0; i <vectorObject.size(); i++)
cout << vectorObject[ i ];
cout << endl;
cout << "Contents of vectorObject2: ";
for(i = 0; i <vectorObject2.size(); i++)
cout << vectorObject2[ i ];
cout << endl;
p = mismatch(vectorObject.begin(), vectorObject.end(), vectorObject2.begin()); // find the first mismatch
if(p.first != vectorObject.end()) { // mismatch found
cout << "The character " << *p.first;
cout << " in vectorObject mismatches the character ";
cout << *p.second << " in vectorObject2.";
}
return 0;
}
Demonstrate random_shuffle() in vector
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
vector<char> vectorObject;
int i;
for(i = 0; i <26; i++)
vectorObject.push_back("A"+i);
cout << "Original contents of vectorObject:\n";
for(i = 0; i <vectorObject.size(); i++)
cout << vectorObject[ i ];
cout << endl;
random_shuffle(vectorObject.begin(), vectorObject.end());
cout << "Shuffled contents of vectorObject:\n";
for(i = 0; i <vectorObject.size(); i++)
cout << vectorObject[ i ];
return 0;
}
Demonstrate search() in vector
#include <iostream>
#include <vector>
#include <algorithm>
#include <cstring>
using namespace std;
int main()
{
vector<char> vectorObject, vectorObject2;
vector<char>::iterator p;
char str1[] = "O, T, T, T";
char str2[] = "T";
int i;
for(i = 0; i <strlen(str1); i++)
vectorObject.push_back(str1[ i ]);
for(i = 0; i <strlen(str2); i++)
vectorObject2.push_back(str2[ i ]);
cout << "Contents of vectorObject: ";
for(i = 0; i <vectorObject.size(); i++)
cout << vectorObject[ i ];
cout << endl;
p = search(vectorObject.begin(), vectorObject.end(), vectorObject2.begin(), vectorObject2.end()); // find the first Two
cout << "Sequence beginning with T: ";
while(p != vectorObject.end())
cout << *p++;
cout << endl;
return 0;
}
Demonstrating partial_sort() in vector
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
void init_vectorObject(vector<int> &vectorObject)
{
vectorObject[0] = 1;
vectorObject[1] = 10;
vectorObject[2] = 2;
vectorObject[3] = -3;
vectorObject[4] = 9;
vectorObject[5] = 4;
vectorObject[6] = 8;
vectorObject[7] = 5;
vectorObject[8] = 7;
vectorObject[9] = 6;
}
int main()
{
vector<int> vectorObject(10);
int i;
init_vectorObject(vectorObject);
cout << "Original order:";
for(i = 0; i <10; i++)
cout << vectorObject[ i ] << " ";
cout << endl;
partial_sort(vectorObject.begin(), vectorObject.begin()+5, vectorObject.end());
cout << "Order after partial sorting:";
for(i = 0; i <10; i++)
cout << vectorObject[ i ] << " ";
cout << endl;
return 0;
}
Demonstrating remove() and replace() in vector
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
vector<char> vectorObject;
vector<char>::iterator p, p_end;
int i;
for(i = 0; i <5; i++) {
vectorObject.push_back("A"+i);
vectorObject.push_back("A"+i);
vectorObject.push_back("A"+i);
}
cout << "Original contents of vectorObject:";
for(p = vectorObject.begin(); p < vectorObject.end(); p++)
cout << *p << " ";
cout << endl;
p_end = remove(vectorObject.begin(), vectorObject.end(), "C"); // remove all C"s
cout << "Sequence after removing all C"s:";
for(p = vectorObject.begin(); p < p_end; p++)
cout << *p << " ";
cout << endl;
replace(vectorObject.begin(), vectorObject.end(), "D", "X"); // replace D"s with digits X"s
cout << "Sequence after replacement:";
for(p = vectorObject.begin(); p < p_end; p++)
cout << *p << " ";
cout << endl;
return 0;
}
Demonstrating sort() in vector
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
void init_v(vector<int> &vectorObject)
{
vectorObject[0] = 1;
vectorObject[1] = 10;
vectorObject[2] = 2;
vectorObject[3] = -3;
vectorObject[4] = 9;
vectorObject[5] = 4;
vectorObject[6] = 8;
vectorObject[7] = 5;
vectorObject[8] = 7;
vectorObject[9] = 6;
}
int main()
{
vector<int> vectorObject(10);
int i;
// sort the entire container
init_v(vectorObject);
cout << "Sort an entire container.";
cout << "Original order:";
for(i = 0; i <10; i++)
cout << vectorObject[ i ] << " ";
cout << endl;
sort(vectorObject.begin(), vectorObject.end());
cout << "Order after sorting container:";
for(i = 0; i <10; i++)
cout << vectorObject[ i ] << " ";
cout << endl;
// sort a subset of the container
init_v(vectorObject);
cout << "Sort a subset of a container.";
cout << "Original order:";
for(i = 0; i <10; i++)
cout << vectorObject[ i ] << " ";
cout << endl;
sort(vectorObject.begin() + 2, vectorObject.end() - 2);
cout << "Order after sorting vectorObject[2] through vectorObject[7]:";
for(i = 0; i <10; i++)
cout << vectorObject[ i ] << " ";
cout << endl;
return 0;
}
Demonstrating unique() in vector
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
vector<char> vectorObject;
vector<char>::iterator p, p_end;
int i;
for(i = 0; i <5; i++) {
vectorObject.push_back("A"+i);
vectorObject.push_back("A"+i);
vectorObject.push_back("A"+i);
}
cout << "Original contents of vectorObject:\n";
for(p = vectorObject.begin(); p < vectorObject.end(); p++)
cout << *p << " ";
cout << endl;
p_end = unique(vectorObject.begin(), vectorObject.end()); // remove duplicates
cout << "Sequence after removing duplicates:\n";
for(p = vectorObject.begin(); p < p_end; p++)
cout << *p << " ";
cout << endl;
return 0;
}
Exchange elements from two different types of containers.
#include <iostream>
#include <vector>
#include <deque>
#include <algorithm>
using namespace std;
int main()
{
vector<char> vectorObject(10);
deque<char> deq(10);
int i;
for(i = 0; i < 10; i++)
vectorObject[ i ] = "A" + i;
for(i = 0; i < 10; i++)
deq[ i ] = "0" + i;
cout << "Original contents of vectorObject:";
for(i = 0; i < 10; i++)
cout << vectorObject[ i ] << " ";
cout << endl;
cout << "Original contents of deq:";
for(i = 0; i < 10; i++)
cout << deq[ i ] << " ";
cout << endl;
// swap ranges in vectorObject and deq
swap_ranges(vectorObject.begin() + 2, vectorObject.end() - 3, deq.begin() + 4);
cout << "Contents of vectorObject after swap:";
for(i = 0; i < 10; i++)
cout << vectorObject[ i ] << " ";
cout << endl;
cout << "Contents of deq after swap:";
for(i = 0; i < 10; i++)
cout << deq[ i ] << " ";
cout << endl;
return 0;
}
Find minimum and maximum inside a vector
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
vector<int> vectorObject(5);
int i;
vectorObject[0] = 1;
vectorObject[1] = 2;
vectorObject[2] = 5;
vectorObject[3] = 9;
vectorObject[4] = 2;
cout << "Contents of vectorObject: ";
for(i = 0; i <vectorObject.size(); i++)
cout << vectorObject[ i ] << " ";
cout << endl;
cout << "Maximum element is: ";
cout << *max_element(vectorObject.begin(), vectorObject.end());
cout << endl;
cout << "Minimum element is: ";
cout << *min_element(vectorObject.begin(), vectorObject.end());
return 0;
}
Generating a sequence in vector
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
double f() // A simple generator function.
{
static double val = 1.0;
double t;
t = 1.0 / val;
val += val;
return t;
}
int main()
{
vector<double> vectorObject(5);
int i;
generate(vectorObject.begin(), vectorObject.end(), f); // generate a series
cout << "Series: ";
for(i = 0; i <vectorObject.size(); i++)
cout << vectorObject[ i ] << " ";
return 0;
}
Insert one vector into another using an insert iterator
#include <iostream>
#include <iterator>
#include <vector>
#include <string>
using namespace std;
int main()
{
vector<string> vectorObject, vectorObject2;
vector<string>::iterator itr;
vectorObject.push_back("T");
vectorObject.push_back("S");
vectorObject.push_back("A");
vectorObject.push_back("P");
vectorObject2.push_back("A");
vectorObject2.push_back("I");
vectorObject2.push_back("S");
cout << "Original size of vectorObject: " << vectorObject.size() << endl;
cout << "Original contents of vectorObject:\n";
itr = vectorObject.begin();
while(itr != vectorObject.end())
cout << *itr++ << " ";
cout << endl;
copy(vectorObject2.begin(), vectorObject2.end(), inserter(vectorObject, vectorObject.begin() + 2));
cout << "Size of vectorObject after insertion: ";
cout << vectorObject.size() << endl;
cout << "Contents of vectorObject after insertion:";
itr = vectorObject.begin();
while(itr != vectorObject.end())
cout << *itr++ << " ";
return 0;
}
Merge two sequences
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
vector<char> vectorObject1, vectorObject2, vectorObject3(26);
int i;
for(i = 0; i <26; i+=2)
vectorObject1.push_back("A"+i);
for(i = 0; i <26; i+=2)
vectorObject2.push_back("B"+i);
cout << "Original contents of vectorObject1:";
for(i = 0; i <vectorObject1.size(); i++)
cout << vectorObject1[ i ];
cout << endl;
cout << "Original contents of vectorObject2:";
for(i = 0; i <vectorObject2.size(); i++)
cout << vectorObject2[ i ];
cout << endl;
merge(vectorObject1.begin(), vectorObject1.end(), // merge sequences
vectorObject2.begin(), vectorObject2.end(),
vectorObject3.begin());
cout << "Result of merge:\n";
for(i = 0; i <vectorObject3.size(); i++)
cout << vectorObject3[ i ];
return 0;
}
Right-rotate a sequence in vector
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
vector<int> vectorObject;
vector<int>::iterator p;
int i;
for(i = 0; i <10; i++)
vectorObject.push_back(i);
cout << "Original ordering: ";
for(p=vectorObject.begin(); p<vectorObject.end(); p++)
cout << *p << " ";
cout << endl;
// rotate right two positions using reverse iterators
rotate(vectorObject.rbegin(), vectorObject.rbegin()+2, vectorObject.rend());
cout << "Order after two right rotates: ";
for(p=vectorObject.begin(); p<vectorObject.end(); p++)
cout << *p << " ";
cout << endl;
return 0;
}
Rotate a sequence in vector
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
vector<int> vectorObject;
vector<int>::iterator p;
int i;
for(i = 0; i <10; i++)
vectorObject.push_back(i);
cout << "Original ordering: ";
for(p=vectorObject.begin(); p<vectorObject.end(); p++)
cout << *p << " ";
cout << endl;
rotate(vectorObject.begin(), vectorObject.begin()+1, vectorObject.end()); // rotate left one position
cout << "Order after left rotate: ";
for(p=vectorObject.begin(); p<vectorObject.end(); p++)
cout << *p << " ";
cout << endl;
return 0;
}
set_union, set_difference, set_symmetric_difference, set_intersection
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
vector<char> vectorObject1, vectorObject2, v_res(26), vectorObject3;
vector<char>::iterator p, pres_end;
int i;
for(i = 0; i <20; i++)
vectorObject1.push_back("A"+i);
for(i=10; i <26; i++)
vectorObject2.push_back("A"+i);
cout << "Contents of vectorObject1:\n";
for(i = 0; i <vectorObject1.size(); i++)
cout << vectorObject1[ i ];
cout << endl;
cout << "Contents of vectorObject2:\n";
for(i = 0; i <vectorObject2.size(); i++)
cout << vectorObject2[ i ];
cout << endl;
pres_end = set_union(vectorObject1.begin(), vectorObject1.end(), vectorObject2.begin(), vectorObject2.end(), v_res.begin());
cout << "Set union: ";
for(p=v_res.begin(); p!=pres_end; p++)
cout << *p;
cout << endl;
pres_end = set_difference(vectorObject1.begin(), vectorObject1.end(), vectorObject2.begin(), vectorObject2.end(), v_res.begin());
cout << "Set difference: ";
for(p=v_res.begin(); p!=pres_end; p++)
cout << *p;
cout << endl;
pres_end = set_symmetric_difference(vectorObject1.begin(), vectorObject1.end(), vectorObject2.begin(), vectorObject2.end(), v_res.begin());
cout << "Set symmetric difference: ";
for(p=v_res.begin(); p!=pres_end; p++)
cout << *p;
cout << endl;
pres_end = set_intersection(vectorObject1.begin(), vectorObject1.end(), vectorObject2.begin(), vectorObject2.end(), v_res.begin());
cout << "Set intersection: ";
for(p=v_res.begin(); p!=pres_end; p++)
cout << *p;
cout << endl;
// includes
vectorObject3.push_back("A");
vectorObject3.push_back("C");
vectorObject3.push_back("D");
if(includes(vectorObject1.begin(), vectorObject1.end(), vectorObject3.begin(), vectorObject3.end()))
cout << "vectorObject1 includes all of vectorObject3.";
else
cout << "vectorObject3 contains elements not found in vectorObject1.";
return 0;
}
Sorting a vector into descending order in vector
#include <iostream>
#include <vector>
#include <algorithm>
#include <functional>
using namespace std;
int main()
{
vector<char> vectorObject(26);
int i;
for(i = 0; i <vectorObject.size(); i++)
vectorObject[ i ] = "A"+i;
cout << "Original ordering of vectorObject:";
for(i = 0; i <vectorObject.size(); i++)
cout << vectorObject[ i ] << " ";
cout << endl;
// sort into desceding order
sort(vectorObject.begin(), vectorObject.end(), greater<char>());
cout << "After sorting vectorObject using greater():";
for(i = 0; i <vectorObject.size(); i++)
cout << vectorObject[ i ] << " ";
return 0;
}
Transforming a sequence in vector
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
double midpoint(double a, double b)
{
return ((a-b) / 2) + b;
}
int main()
{
vector<double> vectorObject1(5), vectorObject2(5), vectorObject3(5);
int i;
vectorObject1[0] = 110.0;
vectorObject1[1] = 918.6;
vectorObject1[2] = 112.23;
vectorObject1[3] = 818.8;
vectorObject1[4] = -212.01;
vectorObject2[0] = 21.0;
vectorObject2[1] = 31.3;
vectorObject2[2] = 41.19;
vectorObject2[3] = 155.0;
vectorObject2[4] = -2.0;
cout << "Values in vectorObject1: ";
for(i = 0; i <vectorObject1.size(); i++)
cout << vectorObject1[ i ] << " ";
cout << endl;
cout << "Values in vectorObject2: ";
for(i = 0; i <vectorObject2.size(); i++)
cout << vectorObject2[ i ] << " ";
cout << endl;
transform(vectorObject1.begin(), // find midpoints between elements in vectorObject1 those in vectorObject2
vectorObject1.end(),
vectorObject2.begin(),
vectorObject3.begin(),
midpoint);
cout << "Midpoints: ";
for(i = 0; i <vectorObject3.size(); i++)
cout << vectorObject3[ i ] << " ";
return 0;
}
Use a function adaptor in vector
#include <iostream>
#include <vector>
#include <algorithm>
#include <functional>
#include <cstring>
using namespace std;
int main()
{
vector<char *> vectorObject;
vector<char *>::iterator p;
int i;
vectorObject.push_back("One");
vectorObject.push_back("Two");
vectorObject.push_back("Three");
vectorObject.push_back("Four");
vectorObject.push_back("Five");
cout << "Sequence contains:";
for(i = 0; i <vectorObject.size(); i++)
cout << vectorObject[ i ] << " ";
cout << endl;
cout << "Searching sequence for Three.\n";
// use a pointer-to-function adaptor
p = find_if(vectorObject.begin(), vectorObject.end(), not1(bind2nd(ptr_fun(strcmp), "Three")));
if(p != vectorObject.end()) {
cout << "Found.";
cout << "Sequence from that point is:";
do {
cout << *p++ << " ";
} while (p != vectorObject.end());
}
return 0;
}
Use a unary function object to determine even/odd.
#include <iostream>
#include <vector>
#include <algorithm>
#include <functional>
using namespace std;
class isEven: public unary_function<int, bool> {
public:
result_type operator()(argument_type i)
{
return (result_type) !(i%2);
}
};
int main()
{
vector<int> vectorObject;
int i;
for(i = 1; i < 20; i++)
vectorObject.push_back(i);
cout << "Sequence:";
for(i = 0; i <vectorObject.size(); i++)
cout << vectorObject[ i ] << " ";
cout << endl;
i = count_if(vectorObject.begin(), vectorObject.end(), isEven());
cout << i << " numbers are evenly divisible by 2.";
return 0;
}
Use for_each() in vector
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
void show(int i)
{
cout << i << " ";
}
int main()
{
vector<int> vectorObject;
int i;
for(i = 0; i <10; i++)
vectorObject.push_back(i);
cout << "Contents of vectorObject: ";
for_each(vectorObject.begin(), vectorObject.end(), show);
cout << endl;
return 0;
}
Use the logical_not unary function object in vector
#include <iostream>
#include <vector>
#include <functional>
#include <algorithm>
using namespace std;
int main()
{
vector<bool> vectorObject;
int i;
for(i = 1; i < 10; i++)
vectorObject.push_back((bool)(i % 2));
cout << boolalpha; // turn on boolalpha I/O flag
cout << "Original contents of vectorObject:";
for(i = 0; i <vectorObject.size(); i++)
cout << vectorObject[ i ] << " ";
cout << endl;
// use the logical_not function object
transform(vectorObject.begin(), vectorObject.end(), vectorObject.begin(), logical_not<bool>());
cout << "Inverted contents of vectorObject:";
for(i = 0; i <vectorObject.size(); i++)
cout << vectorObject[ i ] << " ";
cout << endl;
return 0;
}
Using copy() in Vector
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
vector<char> vectorObject(10);
vector<char> vectorObject2(10);
int i;
for(i = 0; i < 10; i++)
vectorObject[ i ] = "A" + i;
for(i = 0; i < 10; i++)
vectorObject2[ i ] = "z";
copy(vectorObject.begin(), vectorObject.end(), vectorObject2.begin()); // copy all of vectorObject into vectorObject2
cout << "Contents of vectorObject2 after copy:\n";
for(i = 0; i < 10; i++)
cout << vectorObject2[ i ] << " ";
cout << endl;
for(i = 0; i <10; i++) // re-initialize vectorObject2
vectorObject2[ i ] = "z";
copy(vectorObject.begin() + 2, vectorObject.end() - 2, vectorObject2.begin()); // now copy just part of vectorObject into vectorObject2
cout << "Contents of vectorObject2 after subsequence copy:\n";
for(i = 0; i <10; i++)
cout << vectorObject2[ i ] << " ";
cout << endl;
for(i = 0; i <10; i++) // re-initialize vectorObject2
vectorObject2[ i ] = "z";
// now copy part of vectorObject into middle of vectorObject2
copy(vectorObject.begin() + 2, vectorObject.end() - 2, vectorObject2.begin() + 3);
cout << "Contents of vectorObject2 after copy into middle:\n";
for(i = 0; i <10; i++)
cout << vectorObject2[ i ] << " ";
cout << endl;
return 0;
}
Using swap_ranges() in Vector
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
vector<char> vectorObject(10);
vector<char> vectorObject2(10);
int i;
for(i = 0; i < 10; i++)
vectorObject[ i ] = "A" + i;
for(i = 0; i < 10; i++)
vectorObject2[ i ] = "0" + i;
cout << "Original contents of vectorObject:";
for(i = 0; i < 10; i++)
cout << vectorObject[ i ] << " ";
cout << endl;
cout << "Original contents of vectorObject2:";
for(i = 0; i < 10; i++)
cout << vectorObject2[ i ] << " ";
cout << endl;
// swap ranges in vectorObject and vectorObject2
swap_ranges(vectorObject.begin() + 2, vectorObject.end() - 3, vectorObject2.begin() + 4);
cout << "Contents of vectorObject after swap:";
for(i = 0; i < 10; i++)
cout << vectorObject[ i ] << " ";
cout << endl;
cout << "Contents of vectorObject2 after swap:";
for(i = 0; i < 10; i++)
cout << vectorObject2[ i ] << " ";
cout << endl;
return 0;
}