Reputation: 1287
I am writing a program in Qt. I want to convert a double
into a QString
in C++.
Upvotes: 69
Views: 155271
Reputation: 6487
Use QString's number method (docs are here):
double valueAsDouble = 1.2;
QString valueAsString = QString::number(valueAsDouble);
Upvotes: 114
Reputation: 5305
Building on @Kristian's answer, I had a desire to display a fixed number of decimal places. That can be accomplished with other arguments in the QString::number(...)
function. For instance, I wanted 3 decimal places:
double value = 34.0495834;
QString strValue = QString::number(value, 'f', 3);
// strValue == "34.050"
The 'f'
specifies decimal format notation (more info here, you can also specify scientific notation) and the 3
specifies the precision (number of decimal places). Probably already linked in other answers, but more info about the QString::number
function can be found here in the QString
documentation
Upvotes: 17
Reputation: 1466
Instead of QString::number()
i would use QLocale::toString()
, so i can get locale aware group seperatores like german "1.234.567,89".
Upvotes: 19
Reputation: 708
You can use arg(), as follow:
double dbl = 0.25874601;
QString str = QString("%1").arg(dbl);
This overcomes the problem of: "Fixed precision" at the other functions like: setNum() and number(), which will generate random numbers to complete the defined precision
Upvotes: 9
Reputation: 11144
Check out the documentation
Quote:
QString provides many functions for converting numbers into strings and strings into numbers. See the arg() functions, the setNum() functions, the number() static functions, and the toInt(), toDouble(), and similar functions.
Upvotes: 4