In C#, there are several ways of representing numerical data. Your usage of each will depend on your application. When choosing a data type, think about the following questions:

Do I need a whole number or do I need something that will represent a fraction, or a decimal? If I want to use a decimal, how precise do I need to be? Depending on your application, whether it’s a hobby project or building a B2B financial services software, you’ll need a different data type. Is performance a factor? Most times, choosing a data type that takes up less memory will result in faster applications.

Let’s look at two data types that we can use to represent different numerical values:

Int

An int is a whole integer value, like 4, 100, or 2349. They’re a good way to count units of things. For example, if we wanted to track the number of coin flips a user makes, we’d use an int. It doesn’t make sense to have 0.5 coin flips!

To define a variable with the type int, you would write it as follows:

int variableName = 7;

Double and Decimal

If we need to use a decimal value, we have a few options: float, double, and decimal. These values are useful for anything that requires more precision than a whole number, like measuring the precise location of an object in 3D space.

A double is usually the best choice of the three because it is more precise than a float, but faster to process than a decimal. However, make sure to use a decimal for financial applications, since it is the most precise.

To define a variable with the type double, you would write it as follows:

double variableName = 39.76876;

To define a variable with the type decimal, you would write it as follows:

decimal variableName = 489872.76m;

Don’t forget the m character after the number! This character tells C# that we’re defining a decimal and not a double.