What is the difference between syntax and semantics in programming languages?

Question

What is the difference between syntax and semantics in programming languages (like C, C++)?

Answer 1

Wikipedia has the answer. Read syntax (programming languages) & semantics (computer science) wikipages.

Or think about the work of any compiler or interpreter. The first step is lexical analysis where tokens are generated by dividing string into lexemes then parsing, which build some abstract syntax tree (which is a representation of syntax). The next steps involves transforming or evaluating these AST (semantics).

Also, observe that if you defined a variant of C where every keyword was transformed into its French equivalent (so if becoming si, do becoming faire, else becoming sinon etc etc...) you would definitely change the syntax of your language, but you won't change much the semantics: programming in that French-C won't be easier!

Answer 2

Syntax refers to the structure of a language, tracing its etymology to how things are put together.
For example you might require the code to be put together by declaring a type then a name and then a semicolon, to be syntactically correct.

Type token;

On the other hand, the semantics is about meaning. A compiler or interpreter could complain about syntax errors. Your co-workers will complain about semantics.

Answer 3

Semantics is what your code means--what you might describe in pseudo-code. Syntax is the actual structure--everything from variable names to semi-colons.

Answer 4

• You need correct syntax to compile.
• You need correct semantics to make it work.

Answer 5

The syntax of a programming language is the form of its expressions, statements, and program units. Its semantics is the meaning of those expressions, statements, and program units. For example, the syntax of a Java while statement is

while (boolean_expr) statement

The semantics of this statement form is that when the current value of the Boolean expression is true, the embedded statement is executed. Then control implicitly returns to the Boolean expression to repeat the process. If the Boolean expression is false, control transfers to the statement following the while construct.

Answer 6

Syntax: It is referring to grammatically structure of the language.. If you are writing the c language . You have to very care to use of data types, tokens [ it can be literal or symbol like "printf()". It has 3 tokes, "printf, (, )" ]. In the same way, you have to very careful, how you use function, function syntax, function declaration, definition, initialization and calling of it.

While semantics, It concern to logic or concept of sentence or statements. If you saying or writing something out of concept or logic, then you are semantically wrong.