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How to use QString in Qt
This example demonstrates some basic Qt string functions.
Note:Some of images are from qt Creator IDE V4.5 and the code associated with images can also be executed in carbide c++ 2.0
Various Function and Operators
- If you want to append a certain number of identical characters to the string, use operator+=()
The final content of str is "Hello" followed by ten "X": "HelloXXXXXXXXXX".
- Prepends the string Hello to the beginning of str and returns a reference to this string.
QString str = "world";
The content of str is "Hello world".
- Returns a lowercase copy of the string.
The content of lowerCase is "hello". The content of str is still "HELLO", the method QString::toLower() does not modify the string, it returns a lowercase version of the string.
Code snippet using QString
The following example show the use of QString in a graphical application. QLabel is a widget capable of displaying text or images.
int main(int argc, char *argv)
QApplication app(argc, argv);
QString sizeOfWorld = QString::number(str.size());
// resize the string and removes last two characters
str.resize(3); // str = "wor"
// Add "Hello " at the beginning
str.prepend("Hello "); // str = "Hello wor"
// Add "ld" at the end
str.append("ld"); // str = "Hello world"
// Remove 6 characters at position five, and insert " India" at this position
str.replace(5, 6, " India");
QLabel *label1 = new QLabel(str);
QLabel *label2 = new QLabel(sizeOfWorld);
QVBoxLayout *layout = new QVBoxLayout;
Here is the result of this code on Microsoft Windows: