Converting to C-style strings.
#include <iostream>
#include <string>
using namespace std;
int main()
{
string s( "STRINGS" );
const char *ptr1 = 0;
int len = s.length();
char *ptr2 = new char[ len + 1 ]; // including null
ptr1 = s.data();
// copy characters out of string into allocated memory
s.copy( ptr2, len, 0 );
ptr2[ len ] = 0; // add null terminator
cout << s.c_str() << "\nptr1 is ";
for ( int k = 0; k < len; ++k )
cout << *( ptr1 + k ); // use pointer arithmetic
cout << "\nptr2 is " << ptr2 << endl;
delete [] ptr2;
return 0;
}Loop thourgh all elements in a vector using
/* 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 <vector>
#include <iostream>
using namespace std;
int main()
{
vector<int> coll;
// insert elements from -3 to 9
for (int i=-3; i<=9; ++i) {
coll.push_back (i);
}
/* print all elements
* - NOTE: uses operator < instead of operator !=
*/
vector<int>::iterator pos;
for (pos=coll.begin(); pos<coll.end(); ++pos) {
cout << *pos << " ";
}
cout << endl;
}-3 -2 -1 0 1 2 3 4 5 6 7 8 9
Loop through all elements in a vector using operator [] instead of operator *
/* 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 <vector>
#include <iostream>
using namespace std;
int main()
{
vector<int> coll;
// insert elements from -3 to 9
for (int i=-3; i<=9; ++i) {
coll.push_back (i);
}
/* print all elements
* - NOTE: uses operator [] instead of operator *
*/
for (int i=0; i<coll.size(); ++i) {
cout << coll.begin()[i] << " ";
}
cout << endl;
}-3 -2 -1 0 1 2 3 4 5 6 7 8 9
Use indexer to add elements to a vector
#include <iostream>
#include <cassert>
#include <algorithm>
#include <vector>
#include <deque>
using namespace std;
int main()
{
vector<int> vector1(20);
for (int i = 0; i < 20; ++i)
vector1[i] = i;
vector<int>::iterator pos;
for (pos=vector1.begin(); pos!=vector1.end(); ++pos) {
cout << *pos << " ";
}
return 0;
}0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
Use indexer to reference elements in a vector
/* 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>
using namespace std;
int main()
{
vector<int> coll; // vector container for integer elements
// append elements with values 1 to 6
for (int i=1; i<=6; ++i) {
coll.push_back(i);
}
// print all elements followed by a space
for (int i=0; i<coll.size(); ++i) {
cout << coll[i] << " ";
}
cout << endl;
}1 2 3 4 5 6
