C++ Programming Practices – Why Code in C-Style?

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In discussions about whether to cast the result of malloc or not when coding C, one common argument is that if you cast the result then you can compile your C code with a C++ compiler.

Why would one ever want to do that? If I'm not mistaken, there are C compilers available for almost any platform imaginable, but the opposite is not equally true.

So why do people want to compile their C code with a C++ compiler? Why not just use a C compiler instead? C is tricky enough as it is. Keeping track of all the details that would ensure that it's equivalent (nut just valid) C++ code can be quite tricky, especially since there are quite a lot small things that are valid in both languages, but mean different things. Furthermore, it also makes it impossible to use some of the nice new features in modern C.

So what is the use case of coding "C-style C++"?

Best Answer

Lots of people use C++ as “better C”. And there’s nothing wrong with that. It’s something that’s still very easy to understand for someone who learned only C, and that is better than plain C.

So there’s nothing wrong with writing C code that compiles identical as C++ code.

Related Solutions

Do Fortran compilers really generate faster code than C compilers

IIRC one of the main reasons why Fortran is said to be faster is the absence of pointer aliasing, so they can use optimizations that C compilers can't use:

In FORTRAN, function arguments may not alias each other, and the compiler assumes they do not. This enables excellent optimization, and is one major reason for FORTRAN's reputation as a fast language. (Note that aliasing may still occur within a FORTRAN function. For instance, if A is an array and i and j are indices which happen to have the same value, then A[i] and A[j] are two different names for the same memory location. Fortunately, since the base array must have the same name, index analysis can be done to determine cases where A[i] and A[j] cannot alias.)

But I agree with others here: Comparing the average number of assembler instructions generated for a line of code is complete nonsense. For instance a modern x86 core can execute two instructions in parallel if they don't access the same registers. So you can (in theory) gain a performance increase of 100% for the same set on instructions just by reordering them. Good compilers will also often generate more assembly instructions to get faster code (think loop unrolling, inlining). The total number of assembler instructions says very little about the performance of a piece of code.

Why is x=x++ undefined

Maybe you should first answer the question why it should be defined? Is there any advantage in programming style, readability, maintainability or performance by allowing such expressions with additional side effects? Is

y = x++ + ++x;

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Related Solutions

Do Fortran compilers really generate faster code than C compilers

Why is x=x++ undefined

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