macOS Im new to C. And i keep getting this warning in xCode. Can you help?

[w...b]

So im reading one of these eBooks for C programming. I have done "hello world' (yes i am a complete beginner) and now im doing this one that prints at a calculation of temperatures - F vs C.

But i keep getting this warning - 'return types defaults to 'int''

 

[lee1210]

for main's signature, use:

int main(int argc, char *argv[])

rather than

main()

I don't think we need a debate about what's "most right", but it will be easier for you and anyone that reads your code if you use the signature posted above for main.

-Lee

 

[yeroen]

your main() function should be declared (minimally) as

int main()


Pre-ANSI C allowed main to be declared without a return type, or a return type of void. These days, you declare it as returning an int.

 

[w...b]

your main() function should be declared (minimally) as

int main()


Pre-ANSI C allowed main to be declared without a return type, or a return type of void. These days, you declare it as returning an int.

Thanks for the quick help

 

[Sander]

By the way: if your ebook is advocating the old-fashioned main(), it may have other flaws. It's not like the proper signature has become standard last week or so.

Disclaimer: I wrote a programming book myself so I am probably biased.

 

[Cromulent]

By the way: if your ebook is advocating the old-fashioned main(), it may have other flaws. It's not like the proper signature has become standard last week or so.

Disclaimer: I wrote a programming book myself so I am probably biased.

He is using "The C Programming Language" So it is a good quality book .

I recognise the exercise.

Edit: Technically it should be

int main(void) or int main(int argc, char *argv[]) they are the only two correct usages according to the standard. Everything else is implementation defined.

 

[toddburch]

Is the 3rd optional parm for environment variables not standard?

 

[iShater]

And for the love of God, start indenting better, it will help you later when you get used to it.

 

[Cromulent]

Is the 3rd optional parm for environment variables not standard?

No that is an OS level thing not a language feature.

 

[killerwhack]

Indent the Declarations?

And for the love of God, start indenting better, it will help you later when you get used to it.

What is your opinion on the subject question? Is it better to indent everything between the braces ?

What do you think about having the first brace at the end of the line above rather than on it's own line?

 

[Cromulent]

What is your opinion on the subject question? Is it better to indent everything between the braces ?

What do you think about having the first brace at the end of the line above rather than on it's own line?

You always indent another level for another layer of braces. This is a simple example:

int main(void)
{
    //blah
    if(something == 5)
    {
         //blah
         if(somethingelse == 7)
         {
             //bah
         }
    }
}

annoyingly tabs don't work properly on this forum. But that should be one tab indent per layer. Most programmers (well the open source projects I have looked into) equate one tab with four spaces.

Some people prefer to declare functions like this though:

int
main(void)

so you can see the name clearly on the left hand side.

It is just worth reading some coding standards guidelines from some open source projects. I recommend reading through the OpenBSD source code as it is very clear and easy to understand code compared to some other open source projects.

 

[fluidedge]

He is using "The C Programming Language" So it is a good quality book .

Really? I thought it was a pretty horrible book to be honest - didn't really TEACH you anything as such, rather just defined everything.

 

[Cromulent]

Really? I thought it was a pretty horrible book to be honest - didn't really TEACH you anything as such, rather just defined everything.

It's the best programming book I've ever read.

If you read it, it teaches you everything you need to know about the language in less than 300 pages. Pretty big achievement when most programming books are a painful 1000+ pages long.