From: shyouhei@...
Date: 2017-02-20T05:11:52+00:00
Subject: [ruby-core:79621] [Ruby trunk Misc#13230][Feedback] Better Do ...	while structure

Issue #13230 has been updated by Shyouhei Urabe.

Status changed from Open to Feedback

I'm sorry but I have to say I don't understand how the construct works.  Looking at the original site there is an example:

```cpp
/* author: ncomputers.org */
#include<iostream>
using namespace std;

int main(){
    unsigned a[]={0,1,2,3,4,5,6,7,8,9};
    do(unsigned b=0){
        cout<<a[b];
    }while(++b<10){
        cout<<',';
    }
    cout<<endl;
    return 0;
}
```

1.  At sight, I have no idea what this code does, nor how it works.
2. By closely looking at the description in http://ncomputers.org/examples/do%20while%201.cpp , it says "prints the content of an array, separating each of its elements by a comma".  Now I'm totally puzzled.  I don't understand why that is possible by the code, especially how the variable `b` changes over time.

Maybe I'm just a hard-headed nuts.

----------------------------------------
Misc #13230: Better Do ... while structure
https://bugs.ruby-lang.org/issues/13230#change-63043

* Author: Jabari Zakiya
* Status: Feedback
* Priority: Normal
* Assignee: 
----------------------------------------
I just saw this, and thought I'd pass it along.

http://ncomputers.org/suggestions/do%20while.cpp

```
Do ... while structure improvement
Sometimes the use of jumps such as: continue, break, goto, call to a function, etc. is necessary to avoid the execution of some instructions.

This is the case of the seed, warp and swap loops of this solution for the n queens problem.

To avoid the use of jumps or tricks like for(;;) if(condition)break; on some of these cases, we are suggesting the below improvement to the do ... while loop str


/* author: ncomputers.org */
int main(){
    // Allow initializers (extra improvement)
    do(bool condition=0){
        // Block A
    }while(condition){
        // Block B
        // Variables declared inside the initializer still visible
    }
    return 0;
}
```



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