C++/Qt/QString
Содержание
Complete demo for QString
<source lang="cpp"> /****************************************************************************
- Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
- All rights reserved.
- Contact: Nokia Corporation (qt-info@nokia.com)
- This file is part of the documentation of the Qt Toolkit.
- $QT_BEGIN_LICENSE:LGPL$
- Commercial Usage
- Licensees holding valid Qt Commercial licenses may use this file in
- accordance with the Qt Commercial License Agreement provided with the
- Software or, alternatively, in accordance with the terms contained in
- a written agreement between you and Nokia.
- GNU Lesser General Public License Usage
- Alternatively, this file may be used under the terms of the GNU Lesser
- General Public License version 2.1 as published by the Free Software
- Foundation and appearing in the file LICENSE.LGPL included in the
- packaging of this file. Please review the following information to
- ensure the GNU Lesser General Public License version 2.1 requirements
- will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
- In addition, as a special exception, Nokia gives you certain additional
- rights. These rights are described in the Nokia Qt LGPL Exception
- version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
- GNU General Public License Usage
- Alternatively, this file may be used under the terms of the GNU
- General Public License version 3.0 as published by the Free Software
- Foundation and appearing in the file LICENSE.GPL included in the
- packaging of this file. Please review the following information to
- ensure the GNU General Public License version 3.0 requirements will be
- met: http://www.gnu.org/copyleft/gpl.html.
- If you have questions regarding the use of this file, please contact
- Nokia at qt-info@nokia.com.
- $QT_END_LICENSE$
-
- /
- include <QtGui>
- include <QApplication>
- include <stdio.h>
class Widget : public QWidget { public:
Widget(QWidget *parent = 0); void constCharPointer(); void constCharArray(); void characterReference(); void atFunction(); void stringLiteral(); void modify(); void index(); QString boolToString(bool b); void nullVsEmpty(); void appendFunction(); void argFunction(); void chopFunction(); void compareFunction(); void compareSensitiveFunction(); void containsFunction(); void countFunction(); void dataFunction(); void endsWithFunction(); void fillFunction(); void fromRawDataFunction(); void indexOfFunction(); void firstIndexOfFunction(); void insertFunction(); void isNullFunction(); void isEmptyFunction(); void lastIndexOfFunction(); void leftFunction(); void leftJustifiedFunction(); void leftRefFunction(); void midFunction(); void midRefFunction(); void numberFunction(); void prependFunction(); void removeFunction(); void replaceFunction(); void reserveFunction(); void resizeFunction(); void rightFunction(); void rightJustifiedFunction(); void rightRefFunction(); void sectionFunction(); void setNumFunction(); void simplifiedFunction(); void sizeFunction(); void splitFunction(); void splitCaseSensitiveFunction(); void sprintfFunction(); void startsWithFunction(); void toDoubleFunction(); void toFloatFunction(); void toIntFunction(); void toLongFunction(); void toLongLongFunction(); void toLowerFunction(); void toShortFunction(); void toUIntFunction(); void toULongFunction(); void toULongLongFunction(); void toUShortFunction(); void toUpperFunction(); void trimmedFunction(); void truncateFunction(); void plusEqualOperator(); void arrayOperator();
}; Widget::Widget(QWidget *parent)
: QWidget(parent)
{ } void Widget::constCharPointer() {
QString str = "Hello";
} void Widget::constCharArray() {
static const QChar data[4] = { 0x0055, 0x006e, 0x10e3, 0x03a3 };
QString str(data, 4);
} void Widget::characterReference() {
QString str;
str.resize(4);
str[0] = QChar("U");
str[1] = QChar("n");
str[2] = QChar(0x10e3);
str[3] = QChar(0x03a3);
} void Widget::atFunction() {
QString str;
for (int i = 0; i < str.size(); ++i) {
if (str.at(i) >= QChar("a") && str.at(i) <= QChar("f"))
qDebug() << "Found character in range [a-f]";
}
} void Widget::stringLiteral() {
QString str;
if (str == "auto" || str == "extern"
|| str == "static" || str == "register") {
// ...
}
} void Widget::modify() {
QString str = "and";
str.prepend("rock "); // str == "rock and"
str.append(" roll"); // str == "rock and roll"
str.replace(5, 3, "&"); // str == "rock & roll"
} void Widget::index() {
QString str = "We must be bold, very bold";
int j = 0;
while ((j = str.indexOf("", j)) != -1) {
qDebug() << "Found <b> tag at index position" << j;
++j;
}
}
QString Widget::boolToString(bool b)
{
QString result;
if (b)
result = "True";
else
result = "False";
return result;
}
void Widget::nullVsEmpty() {
QString().isNull(); // returns true
QString().isEmpty(); // returns true
QString("").isNull(); // returns false
QString("").isEmpty(); // returns true
QString("abc").isNull(); // returns false
QString("abc").isEmpty(); // returns false
} void Widget::appendFunction() {
QString x = "free"; QString y = "dom"; x.append(y); // x == "freedom"
x.insert(x.size(), y);
} void Widget::argFunction() {
QString i; // current file"s number
QString total; // number of files to process
QString fileName; // current file"s name
QString status = QString("Processing file %1 of %2: %3")
.arg(i).arg(total).arg(fileName);
QString str;
str = "%1 %2";
str.arg("%1f", "Hello"); // returns "%1f Hello"
str.arg("%1f").arg("Hello"); // returns "Hellof %2"
str = QString("Decimal 63 is %1 in hexadecimal")
.arg(63, 0, 16);
// str == "Decimal 63 is 3f in hexadecimal"
QLocale::setDefault(QLocale(QLocale::English, QLocale::UnitedStates));
str = QString("%1 %L2 %L3")
.arg(12345)
.arg(12345)
.arg(12345, 0, 16);
// str == "12345 12,345 3039"
} void Widget::chopFunction() {
QString str("LOGOUT\r\n");
str.chop(2);
// str == "LOGOUT"
} void Widget::compareFunction() {
int x = QString::compare("auto", "auto"); // x == 0
int y = QString::compare("auto", "car"); // y < 0
int z = QString::compare("car", "auto"); // z > 0
} void Widget::compareSensitiveFunction() {
int x = QString::compare("aUtO", "AuTo", Qt::CaseInsensitive); // x == 0
int y = QString::compare("auto", "Car", Qt::CaseSensitive); // y > 0
int z = QString::compare("auto", "Car", Qt::CaseInsensitive); // z < 0
} void Widget::containsFunction() {
QString str = "Peter Pan";
str.contains("peter", Qt::CaseInsensitive); // returns true
} void Widget::countFunction() {
QString str = "banana and panama";
str.count(QRegExp("a[nm]a")); // returns 4
} void Widget::dataFunction() {
QString str = "Hello world";
QChar *data = str.data();
while (!data->isNull()) {
qDebug() << data->unicode();
++data;
}
} void Widget::endsWithFunction() {
QString str = "Bananas";
str.endsWith("anas"); // returns true
str.endsWith("pple"); // returns false
} void Widget::fillFunction() {
QString str = "Berlin";
str.fill("z");
// str == "zzzzzz"
str.fill("A", 2);
// str == "AA"
} void Widget::fromRawDataFunction() {
QRegExp pattern;
static const QChar unicode[] = {
0x005A, 0x007F, 0x00A4, 0x0060,
0x1009, 0x0020, 0x0020};
int size = sizeof(unicode) / sizeof(QChar);
QString str = QString::fromRawData(unicode, size);
if (str.contains(QRegExp(pattern))) {
// ...
}
} void Widget::indexOfFunction() {
QString x = "sticky question"; QString y = "sti"; x.indexOf(y); // returns 0 x.indexOf(y, 1); // returns 10 x.indexOf(y, 10); // returns 10 x.indexOf(y, 11); // returns -1
} void Widget::firstIndexOfFunction() {
QString str = "the minimum";
str.indexOf(QRegExp("m[aeiou]"), 0); // returns 4
} void Widget::insertFunction() {
QString str = "Meal";
str.insert(1, QString("ontr"));
// str == "Montreal"
} void Widget::isEmptyFunction() {
QString().isEmpty(); // returns true
QString("").isEmpty(); // returns true
QString("x").isEmpty(); // returns false
QString("abc").isEmpty(); // returns false
} void Widget::isNullFunction() {
QString().isNull(); // returns true
QString("").isNull(); // returns false
QString("abc").isNull(); // returns false
} void Widget::lastIndexOfFunction() {
QString x = "crazy azimuths"; QString y = "az"; x.lastIndexOf(y); // returns 6 x.lastIndexOf(y, 6); // returns 6 x.lastIndexOf(y, 5); // returns 2 x.lastIndexOf(y, 1); // returns -1
QString str = "the minimum";
str.lastIndexOf(QRegExp("m[aeiou]")); // returns 8
} void Widget::leftFunction() {
QString x = "Pineapple"; QString y = x.left(4); // y == "Pine"
} void Widget::leftJustifiedFunction() {
QString s = "apple"; QString t = s.leftJustified(8, "."); // t == "apple..."
QString str = "Pineapple"; str = str.leftJustified(5, ".", true); // str == "Pinea"
} void Widget::midFunction() {
QString x = "Nine pineapples"; QString y = x.mid(5, 4); // y == "pine" QString z = x.mid(5); // z == "pineapples"
} void Widget::numberFunction() {
long a = 63; QString s = QString::number(a, 16); // s == "3f" QString t = QString::number(a, 16).toUpper(); // t == "3F"
} void Widget::prependFunction() {
QString x = "ship"; QString y = "air"; x.prepend(y); // x == "airship"
} void Widget::removeFunction() {
QString s = "Montreal"; s.remove(1, 4); // s == "Meal"
QString t = "Ali Baba";
t.remove(QChar("a"), Qt::CaseInsensitive);
// t == "li Bb"
QString r = "Telephone";
r.remove(QRegExp("[aeiou]."));
// r == "The"
} void Widget::replaceFunction() {
QString x = "Say yes!"; QString y = "no"; x.replace(4, 3, y); // x == "Say no!"
QString str = "colour behaviour flavour neighbour";
str.replace(QString("ou"), QString("o"));
// str == "color behavior flavor neighbor"
QString s = "Banana";
s.replace(QRegExp("a[mn]"), "ox");
// s == "Boxoxa"
QString t = "A bon mot.";
t.replace(QRegExp("([^<]*)"), "\\emph{\\1}");
// t == "A \\emph{bon mot}."
QString equis = "xxxxxx";
equis.replace("xx", "x");
// equis == "xxx"
} void Widget::reserveFunction() {
QString result;
int maxSize;
bool condition;
QChar nextChar;
result.reserve(maxSize);
while (condition)
result.append(nextChar);
result.squeeze();
} void Widget::resizeFunction() {
QString s = "Hello world"; s.resize(5); // s == "Hello" s.resize(8); // s == "Hello???" (where ? stands for any character)
QString t = "Hello"; t += QString(10, "X"); // t == "HelloXXXXXXXXXX"
QString r = "Hello"; r = r.leftJustified(10, " "); // r == "Hello "
} void Widget::rightFunction() {
QString x = "Pineapple"; QString y = x.right(5); // y == "apple"
} void Widget::rightJustifiedFunction() {
QString s = "apple"; QString t = s.rightJustified(8, "."); // t == "...apple"
QString str = "Pineapple"; str = str.rightJustified(5, ".", true); // str == "Pinea"
} void Widget::sectionFunction() {
QString str; QString csv = "forename,middlename,surname,phone"; QString path = "/usr/local/bin/myapp"; // First field is empty QString::SectionFlag flag = QString::SectionSkipEmpty;
str = csv.section(",", 2, 2); // str == "surname"
str = path.section("/", 3, 4); // str == "bin/myapp"
str = path.section("/", 3, 3, flag); // str == "myapp"
str = csv.section(",", -3, -2); // str == "middlename,surname"
str = path.section("/", -1); // str == "myapp"
QString data = "forename**middlename**surname**phone";
str = data.section("**", 2, 2); // str == "surname"
str = data.section("**", -3, -2); // str == "middlename**surname"
QString line = "forename\tmiddlename surname \t \t phone";
QRegExp sep("\\s+");
str = line.section(sep, 2, 2); // s == "surname"
str = line.section(sep, -3, -2); // s == "middlename surname"
} void Widget::setNumFunction() {
QString str; str.setNum(1234); // str == "1234"
} void Widget::simplifiedFunction() {
QString str = " lots\t of\nwhitespace\r\n "; str = str.simplified(); // str == "lots of whitespace";
} void Widget::sizeFunction() {
QString str = "World"; int n = str.size(); // n == 5 str.data()[0]; // returns "W" str.data()[4]; // returns "d" str.data()[5]; // returns "\0"
} void Widget::splitFunction() {
QString str;
QStringList list;
str = "Some text\n\twith strange whitespace.";
list = str.split(QRegExp("\\s+"));
// list: [ "Some", "text", "with", "strange", "whitespace." ]
str = "This time, a normal English sentence.";
list = str.split(QRegExp("\\W+"), QString::SkipEmptyParts);
// list: [ "This", "time", "a", "normal", "English", "sentence" ]
str = "Now: this sentence fragment.";
list = str.split(QRegExp("\\b"));
// list: [ "", "Now", ": ", "this", " ", "sentence", " ", "fragment", "." ]
} void Widget::splitCaseSensitiveFunction() {
QString str = "a,,b,c";
QStringList list1 = str.split(",");
// list1: [ "a", "", "b", "c" ]
QStringList list2 = str.split(",", QString::SkipEmptyParts);
// list2: [ "a", "b", "c" ]
} void Widget::sprintfFunction() {
size_t BufSize; char buf[BufSize]; ::snprintf(buf, BufSize, "%lld", 123456789LL); QString str = QString::fromAscii(buf);
QString result; QTextStream(&result) << "pi = " << 3.14; // result == "pi = 3.14"
} void Widget::startsWithFunction() {
QString str = "Bananas";
str.startsWith("Ban"); // returns true
str.startsWith("Car"); // returns false
} void Widget::toDoubleFunction() {
QString str = "1234.56"; double val = str.toDouble(); // val == 1234.56
bool ok; double d; d = QString( "1234.56e-02" ).toDouble(&ok); // ok == true, d == 12.3456
QLocale::setDefault(QLocale::C); d = QString( "1234,56" ).toDouble(&ok); // ok == false d = QString( "1234.56" ).toDouble(&ok); // ok == true, d == 1234.56 QLocale::setDefault(QLocale::German); d = QString( "1234,56" ).toDouble(&ok); // ok == true, d == 1234.56 d = QString( "1234.56" ).toDouble(&ok); // ok == true, d == 1234.56
QLocale::setDefault(QLocale::C); d = QString( "1,234,567.89" ).toDouble(&ok); // ok == false
} void Widget::toFloatFunction() {
QString str1 = "1234.56"; str1.toFloat(); // returns 1234.56 bool ok; QString str2 = "R2D2"; str2.toFloat(&ok); // returns 0.0, sets ok to false
} void Widget::toIntFunction() {
QString str = "FF"; bool ok; int hex = str.toInt(&ok, 16); // hex == 255, ok == true int dec = str.toInt(&ok, 10); // dec == 0, ok == false
} void Widget::toLongFunction() {
QString str = "FF"; bool ok; long hex = str.toLong(&ok, 16); // hex == 255, ok == true long dec = str.toLong(&ok, 10); // dec == 0, ok == false
} void Widget::toLongLongFunction() {
QString str = "FF"; bool ok; qint64 hex = str.toLongLong(&ok, 16); // hex == 255, ok == true qint64 dec = str.toLongLong(&ok, 10); // dec == 0, ok == false
} void Widget::toLowerFunction() {
QString str = "Qt by NOKIA"; str = str.toLower(); // str == "qt by nokia"
} void Widget::toShortFunction() {
QString str = "FF"; bool ok; short hex = str.toShort(&ok, 16); // hex == 255, ok == true short dec = str.toShort(&ok, 10); // dec == 0, ok == false
} void Widget::toUIntFunction() {
QString str = "FF"; bool ok; uint hex = str.toUInt(&ok, 16); // hex == 255, ok == true uint dec = str.toUInt(&ok, 10); // dec == 0, ok == false
} void Widget::toULongFunction() {
QString str = "FF"; bool ok; ulong hex = str.toULong(&ok, 16); // hex == 255, ok == true ulong dec = str.toULong(&ok, 10); // dec == 0, ok == false
} void Widget::toULongLongFunction() {
QString str = "FF"; bool ok; quint64 hex = str.toULongLong(&ok, 16); // hex == 255, ok == true quint64 dec = str.toULongLong(&ok, 10); // dec == 0, ok == false
} void Widget::toUShortFunction() {
QString str = "FF"; bool ok; ushort hex = str.toUShort(&ok, 16); // hex == 255, ok == true ushort dec = str.toUShort(&ok, 10); // dec == 0, ok == false
} void Widget::toUpperFunction() {
QString str = "TeXt"; str = str.toUpper(); // str == "TEXT"
} void Widget::trimmedFunction() {
QString str = " lots\t of\nwhitespace\r\n "; str = str.trimmed(); // str == "lots\t of\nwhitespace"
} void Widget::truncateFunction() {
QString str = "Vladivostok"; str.truncate(4); // str == "Vlad"
} void Widget::plusEqualOperator() {
QString x = "free"; QString y = "dom"; x += y; // x == "freedom"
} void Widget::arrayOperator() {
QString str;
if (str[0] == QChar("?"))
str[0] = QChar("_");
} void Widget::midRefFunction() { //! [midRef]
QString x = "Nine pineapples"; QStringRef y = x.midRef(5, 4); // y == "pine" QStringRef z = x.midRef(5); // z == "pineapples"
//! [midRef] } void Widget::leftRefFunction() { //! [leftRef]
QString x = "Pineapple"; QStringRef y = x.leftRef(4); // y == "Pine"
//! [leftRef] } void Widget::rightRefFunction() { //! [rightRef]
QString x = "Pineapple"; QStringRef y = x.rightRef(5); // y == "apple"
//! [rightRef] }
int main(int argc, char *argv[]) {
QApplication app(argc, argv); Widget widget; widget.show(); return app.exec();
}
</source>
cpp with 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. * */
- include <QObject>
- include <QtDebug>
- include <QString>
class MyClass : public QObject { public:
MyClass( const QString &text, QObject *parent = 0 ); const QString &text(); void setText( const QString &text ); int getLengthOfText();
private:
QString m_text;
}; MyClass::MyClass( const QString &text, QObject *parent ) : QObject( parent ) {
m_text = text;
} const QString &MyClass::text() { return m_text; } void MyClass::setText( const QString &text ) { m_text = text; } int MyClass::getLengthOfText() { return m_text.size(); } int main( int argc, char **argv ) {
QObject parent;
MyClass *a, *b, *c;
a = new MyClass( "foo", &parent );
b = new MyClass( "ba-a-ar", &parent );
c = new MyClass( "baz", &parent );
qDebug() << a->text() << " (" << a->getLengthOfText() << ")";
a->setText( b->text() );
qDebug() << a->text() << " (" << a->getLengthOfText() << ")";
return a->getLengthOfText() - c->getLengthOfText();
}
</source>
extends QString
<source lang="cpp">
- include <QList>
- include <QtAlgorithms> // for qSort()
- include <QStringList>
- include <QDebug>
class CaseIgnoreString : public QString { public:
CaseIgnoreString(const QString& other = QString()) : QString(other) {}
bool operator<(const QString & other) const {
return toLower() < other.toLower();
}
bool operator==(const QString& other) const {
return toLower() == other.toLower();
}
}; int main() {
CaseIgnoreString s1("A"), s2("b"), s3 ("C"), s4("d"), s5 ("D");
QList<CaseIgnoreString> namelist;
namelist << s5 << s1 << s3 << s4 << s2;
qSort(namelist.begin(), namelist.end());
int i=0;
foreach (QString stritr, namelist) {
qDebug() << QString("namelist[%1] = %2").arg(i++).arg(stritr) ;
}
QStringList strlist;
strlist << s5 << s1 << s3 << s4 << s2;
qSort(strlist.begin(), strlist.end());
qDebug() << "StringList sorted: " + strlist.join(", ") << endl;
return 0;
}
</source>
Format command line parameter with QString
<source lang="cpp">
- include <QTextStream>
- include <QCoreApplication>
- include <QStringList>
int main (int argc, char* argv[]) {
QCoreApplication app(argc, argv);
QTextStream cout(stdout, QIODevice::WriteOnly);
QStringList arglst = app.arguments();
cout << "argc = " << argc << endl;
for (int i=0; i<arglst.size(); ++i) {
cout << QString("argv#%1 is %2").arg(i).arg(arglst[i]) << endl;
}
int num = arglst[argc - 1].toInt();
cout << num * 2 << endl;
}
</source>
Qt type size
<source lang="cpp">
- include <QString>
- include <QTextStream>
int main() {
QTextStream cout(stdout); char* charp = array1; QString qstring = "This is a unicode QString." ; Q_ASSERT (sizeof(i) == sizeof(int)); cout << " c type sizes: \n"; cout << " qt type sizes: \n"; cout << "sizeof(qstring) = " << sizeof(qstring) << endl; cout << "sizeof(qint32) = " << sizeof (qint32) << "\n"; cout << "sizeof(qint64) = " << sizeof(qint64) << "\n"; cout << "sizeof(qchar) = " << sizeof (QChar) << endl; cout << "qstring.length() = " << qstring.length() << endl; return 0;
}
</source>
Using QString as the parameter
<source lang="cpp">
- include <QString>
- include <qstd.h>
using namespace qstd; class Person { public:
void setNameV( QString newName) {
newName += " A";
m_Name = newName;
}
void setNameCR( const QString& newName) {
m_Name = newName;
}
void setNameR( QString& newName) {
newName += " B";
m_Name = newName;
}
QString m_Name;
};
int main() {
Person p;
QString name("1");
p.setNameCR(name);
p.setNameCR("2");
p.setNameV("3");
p.setNameR(name);
cout << name;
}
</source>
