C++/Qt/QSet

Add to QSet

<source lang="cpp">

1. include <QSet>
2. include <QDebug>

int main() {

 QSet<int> set1;
 set1 << 1 << 2 << 3 << 4 << 5 << 6;
 QSet<int> set2;
 set2 << 4 << 5 << 6 << 7 << 8 << 9;
 set1.subtract(set2);
 // output: 1, 2, 3
 qDebug() << "set1 remainders:" << set1;
 return 0;

}

 </source>

QSet for QString

<source lang="cpp"> /*

* Copyright (c) 2006-2007, Johan Thelin
* 
* All rights reserved.
* 
* Redistribution and use in source and binary forms, with or without modification, 
* are permitted provided that the following conditions are met:
* 
*     * Redistributions of source code must retain the above copyright notice, 
*       this list of conditions and the following disclaimer.
*     * Redistributions in binary form must reproduce the above copyright notice,  
*       this list of conditions and the following disclaimer in the documentation 
*       and/or other materials provided with the distribution.
*     * Neither the name of APress nor the names of its contributors 
*       may be used to endorse or promote products derived from this software 
*       without specific prior written permission.
* 
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/

1. include <QMap>
2. include <QHash>
3. include <QSet>
4. include <QMultiMap>
5. include <QMultiHash>
6. include <QString>
7. include <QtDebug>

void mapStringIntDemo() {

 QMap<QString, int> map;
 
 map["foo"] = 42;
 map["bar"] = 13;
 map["baz"] = 9;
 QString key;
 foreach( key, map.keys() )
   qDebug() << key << " = " << map[key];
 QMap<QString, int>::ConstIterator ii;
 for( ii = map.constBegin(); ii != map.constEnd(); ++ii )
   qDebug() << ii.key() << " = " << ii.value();
 int sum; 
 sum = map["foo"] + map.value("ingenting");
 
 foreach( key, map.keys() )
   qDebug() << key << " = " << map[key];
 sum = map["foo"] + map["ingenting"];
 
 foreach( key, map.keys() )
   qDebug() << key << " = " << map[key];

} void hashStringIntDemo() {

 QHash<QString, int> hash;
 
 hash["foo"] = 42;
 hash["bar"] = 13;
 hash["baz"] = 9;
 QString key;
 foreach( key, hash.keys() )
   qDebug() << key << " = " << hash[key];
 int sum; 
 sum = hash["foo"] + hash.value("ingenting");
 
 foreach( key, hash.keys() )
   qDebug() << key << " = " << hash[key];
 sum = hash["foo"] + hash["ingenting"];
 
 foreach( key, hash.keys() )
   qDebug() << key << " = " << hash[key];

} class Person { public:

 Person( QString name, QString number );
 
 QString name() const;
 QString number() const;

private:

 QString m_name, m_number;

}; Person::Person( QString name, QString number ) : m_name( name ), m_number( number ) {} QString Person::name() const { return m_name; } QString Person::number() const { return m_number; } bool operator==( const Person &a, const Person &b ) {

 return (a.name() == b.name()) && (a.number() == b.number());

} uint qHash( const Person &key ) {

 return qHash( key.name() ) ^ qHash( key.number() );

} void hashPersons() {

 QHash<Person, int> hash;
 
 hash[ Person( "Anders", "8447070" ) ] = 10;
 hash[ Person( "Micke", "7728433" ) ] = 20;
 
 qDebug() << hash.value( Person( "Anders", "8447070" ) ); // 10
 qDebug() << hash.value( Person( "Anders", "8447071" ) ); // 0
 qDebug() << hash.value( Person( "Micke", "7728433" ) ); // 20
 qDebug() << hash.value( Person( "Michael", "7728433" ) ); // 0

} void setStringDemo() {

 QSet<QString> set;
 
 set << "Ada" << "C++" << "Ruby";
 
 for( QSet<QString>::ConstIterator ii = set.begin(); ii != set.end(); ++ii )
   qDebug() << *ii;
 if( set.contains( "FORTRAN" ) )
   qDebug() << "FORTRAN is in the set.";
 else
   qDebug() << "FORTRAN is out.";

} void multimapStringIntDemo() {

 QMultiMap<QString, int> multi;
 
 multi.insert( "foo", 10 );
 multi.insert( "foo", 20 );
 multi.insert( "bar", 30 );
 QSet<QString> keys;
 foreach( QString key, multi.keys() )
   keys << key;
   
 foreach( QString key, keys )
   foreach( int value, multi.values(key) )
     qDebug() << key << ": " << value;
 QMultiMap<QString, int>::ConstIterator ii = multi.find( "foo" );
 while( ii != multi.end() && ii.key() == "foo" )
 {
   qDebug() << ii.value();
   ++ii;
 }

} void multihashStringIntDemo() {

 QMultiHash<QString, int> multi;
 
 multi.insert( "foo", 10 );
 multi.insert( "foo", 20 );
 multi.insert( "bar", 30 );
 QSet<QString> keys;
 foreach( QString key, multi.keys() )
   keys << key;
   
 foreach( QString key, keys )
   foreach( int value, multi.values(key) )
     qDebug() << key << ": " << value;
 QMultiHash<QString, int>::ConstIterator ii = multi.find( "foo" );
 while( ii != multi.end() && ii.key() == "foo" )
 {
   qDebug() << ii.value();
   ++ii;
 }

} int main( void ) {

 mapStringIntDemo();
 hashStringIntDemo();
 hashPersons();
 setStringDemo();
 multimapStringIntDemo();
 multihashStringIntDemo();
 
 return 0;

}

 </source>