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Starting a tech startup with C++

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Re: Starting a tech startup with C++

#61

Post by ambulancechaser »

I would like to see one other aspect discussed though: quickness to market.

At my job, we are rewriting some pretty terrible vb5 code. It's easy to just WTF a lot, and complain that there are truly insane things inside of it. The flipside of that, is that this code was quickly built and quickly allowed for a revenue stream.

The author mentioned that thrown away python code provides no value, but I'm not convinced of that statement. The development time could have been significantly shortened, allowing for a revenue stream while the site was rebuilt in C++. While this may seem like wasted development, it could have created incoming money at three months rather than eight months, helping keep the lights on. Further, there are conceivably problems that would come about during development that would impact their design, which they would have to figure out. Solving these problems are irrespective of the language implementation, and using a dynamic but slower language could help them nail down theoretical issues in algorithms, api, and infrastructure, before coding in the c++ system.

A counter point to this though, is that often, there is no budget for a rewrite. I'm wondering if they would be constrained by the prototype becomes long lasting production like in our case.

Re: Starting a tech startup with C++

#62

Post by palunon »

lbrandy wrote: post #38
petke wrote: post #16

> Manual memory management is the most popular misconception of C++. Since C++11, it is now recommended to use std::shared_ptr or std::unique_ptr for automatic memory management. There is a small computational cost to maintaining referenced pointers but it’s minuscule and the safety outweighs this cost. I think another misconception is that you need pointers at all. Smart pointers are still pointers. Its better to us…

Pointers (smart or raw or whatever) get used when you need reference semantics. It's true that value semantics are usually better but not always (eg inheritance). To be sure, though, being able to make proper value types is a strength of C++. Also we should point out most non-trivial value types make extensive (and necessary!) use of the heap under the hood (eg string, vector)

And then, you have Small String Optimization that put the string data back on the stack ;)

Re: Starting a tech startup with C++

#63

Post by palunon »

ilya1 wrote: post #17
blub wrote: post #10

Earlier quoted context omitted.

Programming - principles and practice using C++[1] should be appropriate for beginners. It's a long book at 1000+ pages, but it is designed for novices and explains subjects such as why one needs functions, how to handle errors, GUIs, testing, etc. The C++ Programming language (4th ed)[2] is for experienced programmers. A tour of C++ is the short version of the former.[3] [1]: http://www.stroustrup.com/programming.ht…

Ohh... thnx! Nothing changed since I graduated in 2001 ... I recollect Stroustrup since then. It's still C++ bible.

It isn't the same edition, the language have changed a lot ;)

Re: Starting a tech startup with C++

#65

Post by steveklabnik »

nickpsecurity wrote: post #56
steveklabnik wrote: post #42

Earlier quoted context omitted.

If Rust code is slower than equivalent C++, it's a bug. We track performance bugs, please file them :)

I like the quip but that's barely an answer given OP avoided Rust specifically. There's a difference between a high-performing language in development (and debugging) vs a high-performing language with over a decade of work into its tooling and support. The latter's strengths and weaknesses are known through and through with many implementation and library problems likely worked out long ago. So, if it was apples to…

Absolutely. I was responding more to this conversation than the author; they specifically said "new" languages :)

Your points are all legit. Unfortunately, the only way to get an old language is to start with a new one, and then let time pass.

Re: Starting a tech startup with C++

#66

Post by mathgenius »

thrownaway2424 wrote: post #53
bnastic wrote: post #4

It's sad that you need to justify using one of the most established and longest serving languages/platforms ever.

Indeed, the given strawman alternative languages (Ruby and Python) are far, far worse for productivity. Python changes are totally unreviewable since one cannot in any way reason about the correctness of a function call without reading the definition of the function itself, and all the functions to which it passes the arguments, all the way down, which of course takes forever. At least with C++ you can reason that if…

Type declarations in python have another name: unit tests.

Re: Starting a tech startup with C++

#67

Post by hifier »

thrownaway2424 wrote: post #53
bnastic wrote: post #4

It's sad that you need to justify using one of the most established and longest serving languages/platforms ever.

Indeed, the given strawman alternative languages (Ruby and Python) are far, far worse for productivity. Python changes are totally unreviewable since one cannot in any way reason about the correctness of a function call without reading the definition of the function itself, and all the functions to which it passes the arguments, all the way down, which of course takes forever. At least with C++ you can reason that if…

Ummm, unit tests? The compiler offers a false sense of security. Type safety is not correctness.

Re: Starting a tech startup with C++

#68

Post by axefrog »

ilya1 wrote: post #7

Sounds very inspiring. Any other good places to start learning about C++ 11/14 for complete beginners with JS and other programming languages? I'm very much interested to create proof-of-concept for high performance SaaS services and play with C++ as it might be useful to build Node.js extension later.

Try http://learncpp.com

Re: Starting a tech startup with C++

#69

Post by petke »

pjc50 wrote: post #57
petke wrote: post #31

Earlier quoted context omitted.

Most often you can pass stack values to and from functions without copying. This is because of move constructors, and named return value optimization. Often its slower to use pointers (the indirection). For instance this does not do any expensive copies: std::string getStr() { auto huge_str = getDatabaseDump(); return huge_str; } void readStr(const std::string& str ){ //read str.. } int main() { auto str = getStr();…

But std::string is a wrapper for a heap allocation, and a reference also incurs the same indirection cost as a pointer?

Yes that's true. Internally a lot of library types use heap allocation. Most well designed libraries avoid it if they can, but sometimes the object is simply too large for the stack. For many library types its a undocumented implementation detail we dont know about.

We as users of that library type should not additionally put that object on the heap though, if we dont have too. Its simply unnecessary.

Its makes for one extra unnecessary pointer indirection, it adds unnecessary reference counting if using smart pointers, or unnecessary manual memory management if we use raw pointers. It complicates the interface for our functions if we have to wrap types in smart pointers.

As for c++ references. Yes that's true. As I understand it they are implemented as pointers internally by compilers. But in important ways they behave more like values, rather than pointers. As in if you copy or assign to them, they copy or assign the value (not the pointer). If you take their address they give the address of the value (not the pointer). Because of this there are not as many pitfalls to using them as there is with pointers. I see them mostly just as aliases for values.

In the example above I could have passed the string by value (instead of by reference) to the function. It would still not have done a expensive copy, because of copy elision optimisation. I probably should have done that. It looks a bit funny, and takes some getting used too.

Relevant: https://web.archive.org/web/20140205194657/http://cpp-next.c...

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