CImage::Save file name formatting

Question

In CImage::Save() function, how can I change the file name?

I saw MSDN(https://msdn.microsoft.com/en-us/library/d06f3fhw(v=vs.120).aspx), but I cannot understand.

Also, every example I found used a constant file name. Like below

CImage.A;
A.Save("test.bmp");

I want to save multiple bmp files. (test1, test2, test3.... test'n'...) In other words, how can I do formatting in the first argument of the function???