preset counter variable in a for loop --> 'has no effect' Error

[drug]

On 2/28/20 11:48 AM, Namal wrote:
> Hello,
> 
> I don't understand why this simple code causes a compiler error..
> 
> import std.stdio;
> 
> void main(){
> 
>   int b = 0;
> 
>   for (b; b<3; b++){
>     writeln(b);
>   }
> }
> 
> $Error: b has no effect
> 
> Same works perfectly fine in C++
> 
> #include <iostream>
> 
> int main(){
>   int i = 0;
> 
>   for(i; i<3; i++)
>     std::cout<<i<<'\n';
> }
> 
> Please help me find what I am doing wrong. Thx

D compiler is smart enough to say that the first use of `b` in for loop 
is useless. Use either this variant:
```
import std.stdio;

void main(){

  int b = 0;

  for (; b<3; b++){
    writeln(b);
  }
}
```
or this:
```
import std.stdio;

void main(){

  for (int b; b<3; b++){
    writeln(b);
  }
}
```