Thus far, within a given function, instructions have been executed sequentially, in the same order as written. Of course that is often appropriate! On the other hands if you are planning out instructions, you can get to a place where you say, “Hm, that depends....”, and a choice must be made. The simplest choices are two-way: do one thing is a condition is true, and another (possibly nothing) if the condition is not true.
More syntax for conditions will be introduced later, but for now consider simple arithmetic comparisons that directly translate from math into C#. Try each line separately in csharp
2 < 5;
3 > 7;
int x = 11;
x > 10;
2 * x < x;
You see that conditions are either true or false (with no quotes!). These are the only possible Boolean values (named after 19th century mathematician George Boole). You can also use the abbreviation for the type bool. It is the type of the results of true-false conditions or tests.
The simplest place to use conditions in a decision made with an if statement.
We will consider more complicated conditions later, but this is a quick start.