Kso, I made allot of C++ stuff. I don't know if some of you people even have C++. Well, let's move on. Here are some demos.

Vertical BoxLayout

Code:


#include <QtGui>

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    {
    QWidget *window = new QWidget;
    QPushButton *button1 = new QPushButton("One");
    QPushButton *button2 = new QPushButton("Two");
    QPushButton *button3 = new QPushButton("Three");
    QPushButton *button4 = new QPushButton("Four");
    QPushButton *button5 = new QPushButton("Five");
    QVBoxLayout *layout = new QVBoxLayout;
    layout->addWidget(button1);
    layout->addWidget(button2);
    layout->addWidget(button3);
    layout->addWidget(button4);
    layout->addWidget(button5);

    window->setLayout(layout);
    window->show();
    }
 
    return app.exec();
}

Passing Arguments by Value

Code:

#include <iostream>
#include <string>
using namespace std;
void printMessage(string); 

int main ()
{
  string str;
  cout << "Enter a string: ";
  cin >> str;
  printMessage(str);
  return 0;
}
void printMessage (string s)
{
  cout << "You inputted " << s;
}

Checking If Two Containers

Code:

#include <algorithm>
#include <iostream>
#include <list>
#include <vector>

using namespace std;

int main( )
{
  short v[] = { 1, 2, 3, 4, 5, 6 };

  vector<short> v1( v,v + sizeof( v ) / sizeof( v[0] ) );

  vector<short> v2( v1 );

  if( v1 == v2 )
      cout << "The vectors are equal" << endl;
  else
      cout << "The vectors are not equal"  << endl;

  reverse( v2.begin(), v2.end() );

  if( v1 == v2 )
      cout << "The vector and reversed vector are equal" << endl;
  else
      cout << "The vector and reversed vector are not equal" << endl;

}

Use iterator and reverse

Code:

#include <iostream>
#include <deque>
#include <algorithm>
using namespace std;

void print (int elem)
{
    cout << elem << ' ';
}

int main()
{
    deque<int> coll;

    // insert elements from 1 to 9
    for (int i=1; i<=9; ++i) {
        coll.push_back(i);
    }

    // find position of element with value 2
    deque<int>::iterator pos1;
    pos1 = find (coll.begin(), coll.end(),    // range
                2);                          // value

    // find position of element with value 7
    deque<int>::iterator pos2;
    pos2 = find (coll.begin(), coll.end(),    // range
                7);                          // value

    // print all elements in range [pos1,pos2)
    for_each (pos1, pos2,    // range
              print);        // operation
    cout << endl;

    // convert iterators to reverse iterators
    deque<int>::reverse_iterator rpos1(pos1);
    deque<int>::reverse_iterator rpos2(pos2);

    // print all elements in range [pos1,pos2) in reverse order
    for_each (rpos2, rpos1,  // range
              print);        // operation
    cout << endl;
}


Erase first element

Code:

#include <iostream>
using std::cout;
using std::endl;

#include <vector>    // vector class-template definition
#include <algorithm> // copy algorithm
#include <iterator>  // ostream_iterator iterator
#include <stdexcept> // out_of_range exception

int main()
{
  int array[ 6 ] = { 1, 2, 3, 4, 5, 6 };
  std::vector< int > integers( array, array + 6 );
  std::ostream_iterator< int > output( cout, " " );

  integers.push_back( 2 );
  integers.push_back( 3 );
  integers.push_back( 4 );

  cout << "Vector integers contains: ";
  std::copy( integers.begin(), integers.end(), output );

  // erase first element
  integers.erase( integers.begin() );
  cout << "\n\nVector integers after erasing first element: ";
  std::copy( integers.begin(), integers.end(), output );


  return 0;
}

Read data from a file

Code:

#include <algorithm>
#include <fstream>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <numeric>
#include <vector>

using namespace std;

int main( )
{
    ifstream stock_file( "data.txt" );

    vector<float> price( (istream_iterator<float>( stock_file )),istream_iterator<float>() );

    vector<float> percent_change( price.size() );
    adjacent_difference( price.begin(), price.end(),percent_change.begin() );

    copy( price.begin(), price.begin()+5,ostream_iterator<float>( cout,  "  " ) );
}