Lines of code function like sentences, meaning they need to have some sort of separating or ending character. Every line of C#, called a statement, MUST end with a semicolon to separate them for the code compiler to process.
However, there's a catch that you need to be aware of. Unlike the written word we're all familiar with, a C# statement doesn't technically have to be on a single line; whitespace and newlines are ignored by the code compiler. For example, a simple variable could be written like this:
public int firstName = "Harrison";
Alternatively, it could also be written as follows:
public
int
firstName
=
"Harrison";
These two code snippets are both perfectly acceptable to Visual Studio, but the second option is highly discouraged in the software community as it makes code extremely hard to read. The idea is to write your programs as efficiently and clearly as possible.