Re: auto return for some recursive functions in C++11

[MattCoder via Digitalmars-d]

On Wednesday, 14 January 2015 at 22:29:09 UTC, bearophile wrote:

According to Wikipedia:
http://en.wikipedia.org/wiki/C%2B%2B14#Function_return_type_deduction

C++14 is able to compile code like this:


auto correct(int i) {
    if (i == 1)
        return i;
    else
        return correct(i - 1) + i;
}
...

According to the wiki link:

"If multiple return expressions are used in the function's
implementation, then they must all deduce the same type."

So this will NOT work:

auto Correct(int i) {
     if (i == 1){
         return (int)5;
     }else{
         return (float)10;
     }
}

Error:

prog.cpp: In function 'auto Correct(int)':
prog.cpp:8:19: error: inconsistent deduction for 'auto': 'int'
and then 'float'
      return (float)10;
                    ^

So could you please tell me a good use case to for using "return
type deduction"?

Matheus.