Lessons

They say that people with no technical education have no place in programming. They try to frighten you away from thinking about a career change after you hit 30 years. But what if only at age 30 does it become clear that all your previous knowledge and experience led you to the wrong destination? In reality, it isn't so scary. Anyone can become a programmer...

Strict typing sounds tough, militaristic... But don't be afraid, it doesn't hurt! It usually doesn't hurt. In this lesson, we'll talk about the fact that all Java variables (including objects) have a set type beforehand. This type cannot be changed while a command is being executed. This approach has its pluses and minuses.

Java has some obscure types... To avoid clogging up your brain, we only studied and actively used the most common data types in the first levels of CodeGym. Now we'll study others, along with a table that summarizes all the necessary information. And this, above all, is the amount of space allocated to a particular type of variable.

Java's strict typing does not allow data types to be changed. However, there is a way. It's called type casting. And we're not talking about an actor being locked into a particular role. In this context, we mean something else — using assignment to converting a variable of one type to a variable of another type. You'll learn how this happens in Java in this lesson.

The topic of type conversion must be approached responsibly: for many CodeGym students, it seems simple (still, it's Level 10!), but a flippant attitude here leads to numerous programming errors even for "grown up" programmers. So let's build a habit of approaching type conversion correctly. How? By doing tasks, of course.

Despite Java's strict approach of typing, you can turn any data type into a String! Moreover, almost every type can be cast to the String type implicitly. This is immediately evident if we try to add two variables: a String and a "non-String". In this case, the "non-String" variable is converted to a String. It's convenient. Let's learn how to use it!

When compatibles types are converted, the conversion may be narrowing or widening. Today, we'll use the Object class as we look at type conversions. Any reference type can be assigned to such a variable (type narrowing). But what if you need to perform a widening conversion? You'll learn in the lesson.

The first quest is coming to an end! This crucial moment is the best time to repeat the material and reinforce your knowledge through practice. Accordingly, in this block we have prepared tasks on various topics, and even several problems that are more advanced. If something isn't clear, you can google it. Think and google, got it? Good luck!