Qt常用類

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向控制臺輸出文本

第一個例子，我們采用STL的方式：

console.cpp #include <iostream>int main() {std::cout << "console application\n"; }

第二個例子我們用QT4編程庫

console2.cpp #include <QTextStream>int main() {QTextStream out(stdout);out << "console application\n"; }

Output

console application

QFile

寫一行字符串到文件中

file.cpp #include <QTextStream> #include <QFile>int main() {QFile data("myfile");if (data.open(QFile::WriteOnly)) {QTextStream out(&data);out << "You make me want to be a better man." << endl;} } Output $ cat myfile You make me want to be a better man.

下面的例子我們輸出一段文本到控制臺

szerelem S a régi szeret?mér- mit nem cselekednék, tengerb?l a vizet kanállal lemerném.S a tenger fenekér?l apró gy?ngy?t szednék, s a régi szeret?mnek gy?ngykoszorút k?tnék. szerelem.cpp #include <QTextStream> #include <QFile>int main() {QFile data("szerelem");QString line;if (data.open(QFile::ReadOnly)) {QTextStream in(&data);QTextStream out(stdout);out.setCodec("UTF-8");in.setCodec("UTF-8");do {line = in.readLine();out << line << endl;} while (!line.isNull());} } Output S a régi szeret?mér- mit nem cselekednék, tengerb?l a vizet kanállal lemerném.S a tenger fenekér?l apró gy?ngy?t szednék, s a régi szeret?mnek gy?ngykoszorút k?tnék.

QList

Qt容器類之一

mlist.cpp #include <QTextStream> #include <QList>int main() {QTextStream out(stdout);QList<QString> list;list << "Balzac" << "Tolstoy" << "Guldbrassen"<< "London" << "Galsworthy" << "Sienkiewicz";qSort(list);for (int i = 0; i < list.size(); ++i) {out << list.at(i) << endl;}}

Output

Balzac Galsworthy Guldbrassen London Sienkiewicz Tolstoy

QDir

管理文件目錄

home.cpp #include <QTextStream> #include <QDir>int main() {QTextStream out(stdout);QString home = QDir::homePath();out << home << endl; }

Output

/home/vronskij

輸出應用程序所在路徑中擴展名是.c的全部文件名字

filters.cpp #include <QTextStream> #include <QDir>int main() {QTextStream out(stdout);QDir dir;QStringList filters;filters << "*.c" << "*.c~";dir.setNameFilters(filters);QFileInfoList list = dir.entryInfoList();for (int i = 0; i < list.size(); ++i) {QFileInfo fileInfo = list.at(i);out << QString("%1").arg(fileInfo.fileName());out << endl;} }

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Output $ ls -F anim* anim.c anim.c~ filters* $ ./filters anim.c anim.c~

QTime

輸出當前時間

mtime.cpp #include <QTextStream> #include <QTime>int main() {QTextStream out(stdout);QTime qtime = QTime::currentTime();QString stime = qtime.toString(Qt::LocalDate);out << stime << endl; }

Output

$ ./time 10:30:33 PM

QString

字符串連接

concat.cpp #include <QTextStream>int main() {QString a = "Disziplin ";QString b = "ist ";QString c = "Macht.\n";QTextStream out(stdout);out << a + b + c; }

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Output $ ./concat Disziplin ist Macht.

字符串追加

append.cpp #include <QTextStream>int main() {QString string = "Whether I shall ";string.append("turn out to be the hero of my own life, \n");string.append("or whether that station will be held by anybody else, \n");string.append("these pages must show.\n");QTextStream out(stdout);out << string; } Output $ ./append Whether I shall turn out to be the hero of my own life, or whether that station will be held by anybody else, these pages must show.

參數替換

arg.cpp #include <QTextStream>int main() {QString string = "What if I gave you %1 red roses?";int num = 21;QTextStream out(stdout);out << string.arg(num) << endl; } Output $ ./str3 What if I gave you 21 red roses?

輸出字符串長度

size.cpp #include <QTextStream>int main() {QString string = "The history of my life.";QTextStream out(stdout);out << "The string has " + QString::number(string.size())+ " characters." << endl; } Output ./size The string has 23 characters.

字符串大小寫轉換

uplow.cpp #include <QTextStream>int main() {QString string = "The history of my life.";QTextStream out(stdout);out << string.toLower() << endl; out << string.toUpper() << endl; } Output $ ./uplow the history of my life. THE HISTORY OF MY LIFE.

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轉載于:https://www.cnblogs.com/xchsp/p/4063316.html

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