Re: preset counter variable in a for loop

[Namal via Digitalmars-d-learn]

On Friday, 28 February 2020 at 12:48:17 UTC, mipri wrote:

On Friday, 28 February 2020 at 12:44:52 UTC, 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


Well, that's the error. b has no effect, so there's
no need for it, and it's likely written in error. It
has no effect in C++ either, and you may get a warning:

example.cc: In function 'int main()':
example.cc:7:8: warning: statement has no effect 
[-Wunused-value]

  for (b; b<3; b++){


Thanks, I didn't know that you don't need it there and can leave 
it out!

Re: preset counter variable in a for loop

[mipri via Digitalmars-d-learn]

On Friday, 28 February 2020 at 12:44:52 UTC, 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


Well, that's the error. b has no effect, so there's
no need for it, and it's likely written in error. It
has no effect in C++ either, and you may get a warning:

example.cc: In function 'int main()':
example.cc:7:8: warning: statement has no effect [-Wunused-value]
  for (b; b<3; b++){

preset counter variable in a for loop

[Namal via Digitalmars-d-learn]

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 

int main(){
 int i = 0;

 for(i; i<3; i++)
   std::cout<

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

[drug via Digitalmars-d-learn]

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 

int main(){
  int i = 0;

  for(i; i<3; i++)
    std::cout<

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);
 }
}
```

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

[Namal via Digitalmars-d-learn]

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 

int main(){
 int i = 0;

 for(i; i<3; i++)
   std::cout<