How to use it. 1  Open Excel & VBA editor 2  (+) Insert the code below under Sheet1. 3  Go back to Excel and select your desired range to fill with random & non-repeating numbers.  Execute the macro (+)
See also What are the rules about using an underscore in a C++ identifier; a lot of the same rules apply to both C and C++, though the embedded double-underscore rule is in C++ only, as mentioned at the top of this answer. Names with double leading underscores are reserved for use by the implementation.
In C++ there are two types of numbers. Ints and floats. There are also variants of these types that hold bigger numbers, or only unsigned numbers but they are still ints or floats. An int is a whole number like 47 without a decimal point. You can't have 4.5 babies or loop 32.9 times.