QString::arg() Error: Missing Argument - Solution and Explanation

This error message indicates a missing argument in a call to the QString::arg() function. The function expects a value to replace the '%q\n' placeholder in the string, but it's not being provided.

In this specific case, the error message indicates the missing argument should be the value 153. To fix the error, provide this value as an argument to the QString::arg() function, like this:

QString str = "The value is %q\n";
str = str.arg(153);

This replaces the '%q\n' placeholder in the string with the value 153, producing the following output:

'The value is 153\n'