The situation looks like that many authors, and it would be more correct to say the translators, handle the terms operators, instructions, expressions as it is very much at ease. It seems to me that it is especially unacceptable to do this in textbooks, from the very beginning laying down the wrong idea in language learners. I think it is necessary to follow the original sources and call things by their proper names. So, how are these concepts defined, for example, in the Java language? The source says that:
"Operators", and then return a result. https://docs.oracle.com/javase/tutorial/java/nutsandbolts/operators.html
"It is a concept of the vocabulary of the vocabulary." https://docs.oracle.com/javase/tutorial/java/nutsandbolts/expressions.html
"Statements are roughly equivalent to natural language." https://docs.oracle.com/javase/tutorial/java/nutsandbolts/expressions.html
However, in almost all translated textbooks that have become virtually classical (for example, Schildt, Horstmann), the concepts of operators and instructions are mixed everywhere. Operators include control instructions (if, switch) and cycles. And this is despite the fact that the originals use the canonical definition of statements. It seems that such a delusion has happened a long time ago and if and the switch are called operators everywhere. The same applies to the break instruction and case labels. But why, then, are operators called operators, if these are all different concepts? Let me be corrected if I am wrong in something, simply and I myself would like to firmly decide.