我要实现CString变量这样的功能，怎么办?

Question

如果我用如下语句：                                                                                                      
double i = 0.05                                                                                                         
str.Format("%f",i);                                                                                                     
                                                                                                                        
则最后生成的str字符串为0.050000                                                                                         
系统会自动填上0以满足有效位数的需要                                                                                     
有什么办法可以让double转换为str后那些有效位数的0去掉呢？？                                                              
                                                                                                                        
也就是说，如果我的i=0.05，则str要为0.05，而不是0.050000                                                                 
如果我的i = 0.005，则str要为0.005，而不是0.005000                                                                       
如果我的i = 3.0156，则str要为3.0156，而不是3.015600                                                                     
                                                                                                                        
有什么办法可以实现这个功能？？ 

Answer 1

笨办法:手动去cut掉后面的0,呵呵

Answer 2

计算出有效位后，str.Left(3),这样是不是好点？

Answer 3

呵呵,来个投机取巧的double i = 0.05
str.Format("%f",i); 
str.TrimRight('0');

Answer 4

lixiaosan(小三) ( ) 信誉：150 高！

Answer 5

double i = 0.05;
CString str;
str.Format("%0.6f",i);