Computing the sum with template iterators
#include <iostream>
#include <vector>
using std::cout;
using std::endl;
using std::vector;
template <typename Iter>
double vectorSum(Iter begin, Iter end) {
double sum = 0.0;
while( begin != end )
sum += *begin++;
return sum;
}
int main() {
vector<int> sunny;
sunny.push_back(7);
sunny.push_back(12);
sunny.push_back(15);
cout << sunny.size() << " months on record" << endl;
cout << "vectorSum number of sunny days: ";
cout << vectorSum(sunny.begin(), sunny.end()) << endl;
return 0;
}3 months on record
vectorSum number of sunny days: 34
Demonstration of size() and capacity()
#include <iostream>
#include <vector>
int main ()
{
using namespace std;
// Instantiate a vector object that holds 5 integers of default value
vector <int> v (5);
cout << "Size: " << v.size ();
cout << ", Capacity: " << v.capacity () << endl;
// Inserting a 6th element in to the vector
v.push_back (666);
cout << "Size: " << v.size ();
cout << ", Capacity: " << v.capacity () << endl;
// Inserting another element
v.push_back (777);
cout << "After inserting yet another element... " << endl;
cout << "Size: " << v.size ();
cout << ", Capacity: " << v.capacity () << endl;
return 0;
}Put more values onto the end of the vector,it will grow as needed
#include <iostream>
#include <vector>
#include <cctype>
using namespace std;
int main()
{
vector<char> v(10); // create a vector of length 10
unsigned int i;
// display original size of v
cout << "Size = " << v.size() << endl;
// assign the elements of the vector some values
for(i=0; i<10; i++) v[i] = i + "a";
// display contents of vector
cout << "Current Contents:\n";
for(i=0; i<v.size(); i++) cout << v[i] << " ";
cout << "\n\n";
cout << "Expanding vector\n";
for(i=0; i<10; i++) v.push_back(i + 10 + "a");
// display current size of v
cout << "Size now = " << v.size() << endl;
// display contents of vector
cout << "Current contents:\n";
for(i=0; i<v.size(); i++) cout << v[i] << " ";
cout << "\n\n";
// change contents of vector
for(i=0; i<v.size(); i++) v[i] = toupper(v[i]);
cout << "Modified Contents:\n";
for(i=0; i<v.size(); i++) cout << v[i] << " ";
cout << endl;
return 0;
}Show statistics about vector: size, max_size and capacity
#include <iostream>
#include <vector>
using namespace std;
typedef vector<int> INTVECTOR;
int main(void)
{
// Dynamically allocated vector begins with 0 elements.
INTVECTOR theVector;
theVector.push_back(42);
// Show statistics about vector.
cout << "theVector"s size is: " << theVector.size() << endl;
cout << "theVector"s maximum size is: " << theVector.max_size()<< endl;
cout << "theVector"s capacity is: " << theVector.capacity() << endl;
}vector: max_size(), size(), capacity()
/* 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 <string>
#include <algorithm>
#include <iterator>
using namespace std;
int main()
{
// create empty vector for strings
vector<string> sentence;
// reserve memory for five elements to avoid reallocation
sentence.reserve(5);
// append some elements
sentence.push_back("Hello,");
sentence.push_back("how");
sentence.push_back("are");
sentence.push_back("you");
sentence.push_back("?");
// print elements separated with spaces
copy (sentence.begin(), sentence.end(),
ostream_iterator<string>(cout," "));
cout << endl;
cout << " max_size(): " << sentence.max_size() << endl;
cout << " size(): " << sentence.size() << endl;
cout << " capacity(): " << sentence.capacity() << endl;
}Hello, how are you ?
max_size(): 1073741823
size(): 5
capacity(): 5
vector size before and after elements insertion
#include <iostream>
#include <vector>
#include <cctype>
using namespace std;
int main()
{
vector<char> v(10); // create a vector of length 10
cout << "Size = " << v.size() << endl;
for(int i=0; i<10; i++)
v[i] = i + "a";
cout << "Current Contents:\n";
for(int i=0; i<v.size(); i++) cout << v[i] << " ";
cout << "\n\n";
cout << "Expanding vector\n";
for(int i=0; i<10; i++)
v.push_back(i + 10 + "a");
cout << "Size now = " << v.size() << endl;
cout << "Current contents:\n";
for(int i=0; i<v.size(); i++)
cout << v[i] << " ";
cout << "\n\n";
return 0;
}Size = 10
Current Contents:
a b c d e f g h i j
Expanding vector
Size now = 20
Current contents:
a b c d e f g h i j k l m n o p q r s t
