what is syntax and semantics in c++?

Answer 1

A programming language is a set of rules, symbols, and special words used to construct a program. In particular, there are rules for both syntax (grammar) and semantics (meaning). ... Syntax rules are the blueprints we use to build instructions in a program.

Answer 2

Any language, formal or not, is defined by three things: lexic, syntax and semantics. The former is about word correctness, the second is about phrase correctness and the later is about phrase meaning.