W3Schools offers free online tutorials and references on web development languages such as HTML, CSS, JavaScript, PHP, SQL, … Learn how to use HTML to display images, set image dimensions, and add alternative text for better accessibility. When you know exactly how many times you want to loop through a block of code, use the for loop instead of a while loop. C++ Structures Structures (also called structs) are a way to group several related variables into one place. Each variable in the … Every variable in Java has a data type - primitive types like int and boolean, or non-primitive types.