C# simple "for" and "int" issue

Question

Im trying to learn C# from scratch and I have issue with one simple task. I cant understand why this is Not working,can you please explain me :

     namespace ConsoleApplication1
{
    class intro
    {
        static void Main(string[] args)
        {
            int i;
            int j;
            for (i = 1; j=-1; i <= 100 && j >= -100; i += 2, j -=2)
            {
                Console.WriteLine(i+j);
            }
        }
    }
}

Edit: I missed why is NOT working, sorry for that. Semicolon instead of colon was the problem... Stupid question but thank you for patience.

Simple. You're looping until `i <= 100 && j >= -100`. Each loop, `i` has 2 added to it.. `j` has 2 removed. You should review basic `for..` loops if you don't understand this. — Simon Whitehead, Feb 06 '14 at 12:45
The code actually doesn't compile. Should be "for(i=1, j=-1" ...comma instead of semicolon. — Grzegorz Sławecki, Feb 06 '14 at 12:48
This site is better for explaining why code is _not_ working. What is your actual question here? — H H, Feb 06 '14 at 12:49
Why this code _is_ working, or why this code _isn't_ working? — Svish, Feb 06 '14 at 12:50
Leaving out a __not__ is a big typo in a question... Also, always provide the full error messages. — H H, Feb 06 '14 at 12:56
Your `for` is doing -1+1 = 0 then +3-3=0 then +5-5=0 then ... then +n-n=0 — Alex, Feb 06 '14 at 13:10
Yes, I just realized this... Thinking is really good thing if you actually can do it... It was stupid question but thank you for patience and answers ! — tslid, Feb 06 '14 at 13:13

score 0 · Answer 1 · answered Feb 06 '14 at 12:49

What do you mean by:

I cant understand why this is working

It is working because it is a valid code.Except this comma should be semicolon:

i = 1; <-- wrong
i = 1, <-- correct

You are constructing a for loop.You define two variable,i and j then,you starting i from 1 and j form -1. Then you specify the loop condition. i <= 100 && j >= -100.With this condition you are saying the loop should execute as long as i <= 100 AND j >= -100 And last statement you specifying the expression which will be executed in every step.That's it.

score 0 · Answer 2 · answered Feb 06 '14 at 12:50

0

for loop needs to have a structure of

for (initializer; condition; iterator)
    body

Please refer to MSDN, these are the most basics of every programming language.

answered Feb 06 '14 at 12:50

Tarec

3,268
4
30
47

Iqbal · Accepted Answer · 2014-02-06T13:00:00.923

0

There is a very common mistake, you placed `;' in the place ',';

for (i = 1, j=-1; i <= 100....

I don't know what you want to do with the code but it produce only '0' but the code is working as it should.

edited Feb 06 '14 at 13:00

answered Feb 06 '14 at 12:55

Iqbal

1,266
1
17
21

C# simple "for" and "int" issue

3 Answers3