Q:

How to use Int64 in C#

The question is easy! How do you represent a 64 bit int in C#?

A:

64 bit int is long

A:

System.Int64 is the .net type, in C# it's also called long

A:

A signed 64 bit integer is long, an unsigned is ulong.
The corresponding types in the framwwork are System.Int64 and System.UInt64, respectively.
Example:
long bigNumber = 9223372036854775807;

