double转QString丢失精度

 

 

double a = 12342453434.12345556666;
QString str = QString::number(a);

结果是：

	名称	值	类型
▶	str	1.23425e+10	QString

 

double a = 12342453434.12345556666;
QString str = QString::number(a,'f', 200);
QMessageBox::information(this, "tips", str);

结果：

	名称	值	类型
▶	str	12342453434.12345504760742187500000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000...	QString