A function within a loop, with unchanged arguments

Question

I want to call a function within a loop. The function takes three parameters. I want two of them to stay unchanged within a loop while only the third is affected through my loop.

Edited Version : Here is a sample code:

void Function(int v1, int v2, int v3) {};

int main(int argc, char** argv) { 
    int a;
    int b;

    for (int i = 0; i < 5; ++i) {
        Function(int a, int b, i)
    }
}

This is the error I get when I compile this code :

error: 
      expected expression Function(int v1, int v2, i)....

Is there a way to realize my idea?

**go ahead editing your question**, remove `int`s from calling method which is `main()` — Soner from The Ottoman Empire, Jun 08 '18 at 11:56
still not completed, read my answer then apply what it is written there. — Soner from The Ottoman Empire, Jun 08 '18 at 11:58
**Excellent.** Highly likelihood you don't understand what's going on under the hood?? To do it, look under the hood meaning **COMMENCE READING A C BOOK** — Soner from The Ottoman Empire, Jun 08 '18 at 12:02
https://www.amazon.com/Programming-Absolute-Beginners-Guide-3rd/dp/0789751984/ref=pd_bxgy_14_img_2?_encoding=UTF8&pd_rd_i=0789751984&pd_rd_r=GFYGENHMVVMEFRJRWJAV&pd_rd_w=fsrdd&pd_rd_wg=uUGTb&psc=1&refRID=GFYGENHMVVMEFRJRWJAV — Soner from The Ottoman Empire, Jun 08 '18 at 12:03
I will . Thank you for your input and suggestions . It really helped me! — xava, Jun 08 '18 at 12:04
Dont edit your question to fix the errors you were originally asking for. In its current state your question literally makes no sense, because there is no way the code you show could produce the error you report. — 463035818_is_not_an_ai, Jun 08 '18 at 12:11
Lol. A list of C++ books [here](https://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list). — Paul Sanders, Jun 08 '18 at 12:13
btw I dont understand why snr encouraged you to edit the question and fix the errors.... @snr please dont do that. Questions are for question and for broken code, fixed code goes in the answers — 463035818_is_not_an_ai, Jun 08 '18 at 12:14
@user463035818 < Sir, he started to edit the question from its backbone(s), what should I have done in this case ? — Soner from The Ottoman Empire, Jun 08 '18 at 12:16
@snr i dont really understand why you mean (backbones??), but you should not have told him to edit the question to incorporate the code fixes, because this makes the question completely useless on a Q&A site where question should contain the question and not the answers — 463035818_is_not_an_ai, Jun 08 '18 at 12:17
I wanted just to correct the obvious mistakes, that I did not realize while writing the question ...like missing void. — xava, Jun 08 '18 at 12:17
@snr maybe "go ahead editing your question" was sarcasm, in this case i didnt get it and seems like OP too ;) — 463035818_is_not_an_ai, Jun 08 '18 at 12:18
@xava Don't worry, things will improve as you get a better feel for the site. — Paul Sanders, Jun 08 '18 at 12:19
btw I am not trying to play the "i know how this site works"-police, I am also just a user trying to get the best out of it. Just wanted to give advice ;) — 463035818_is_not_an_ai, Jun 08 '18 at 12:21

mystery_doctor · Answer 1 · 2018-06-08T12:23:22.233

4

You're using the wrong syntax, and that's why you are getting the error.

When declaring a function, you specify the type of the parameters (and don't forget the return type):

void Function(int v1, int v2, int v3) {
    // your function body here
};

When invoking a function, you simply pass the parameters:

Function(1, 2, 3);

In your case, the compiler thought you were trying to declare another function, while in the body of another.

So, in the end, and assuming v1 and v2 are already defined, you need to write your main as

int main () { 

  // don't forget to define v1 and v2
  int v1 = 10;
  int v2 = 20;   

  for (int i=0; i <5; i++) {
    Function(v1, v2, i)
  }
}

Hope this helps!

edited Jun 08 '18 at 12:23

answered Jun 08 '18 at 11:49

mystery_doctor

404
2
11

where is the return type of `Function` ?? I think it is not the adequate answer. If `Function` was return type, where would be its name? – Soner from The Ottoman Empire Jun 08 '18 at 12:00
I completely agree... your answer is much better, so I didn't fix mine. But I'll fix it now... shouldn't leave a misleading answer – mystery_doctor Jun 08 '18 at 12:20
Done, but go easy on the new guy who asked the question. Clearly he's new on the site and is still learning programming – mystery_doctor Jun 08 '18 at 12:32
Okay, thanks for the advice. I've already put it in the back of my mind. – Soner from The Ottoman Empire Jun 08 '18 at 12:34

score 2 · Accepted Answer · answered Jun 08 '18 at 11:48

You forgot, I think you don't know, a host of things. Keep track of the comments. However, you have to read a C book for beginners.

//whereIsReturnTypeofTheFunction ???
void Function(int v1, int v2, int v3) {};

int main () {

    // you need variables to be passed to Function
    int a;
    int b;

    // for condition is vetted by looking i, not int, in the middle
    for (int i=0; i <5; i++) {
        Function(a,  b, i); 

    }
}

score 1 · Answer 3 · edited Jun 08 '18 at 12:13

Do something like

void Function(int v1, int v2, int v3) { };

int main () { 
  int v1 = 0;
  int v2 = 0;
  for (int i = 0; i < 5; i++) {
    Function(v1, v2, i);
  }
}

Some problems with your code:

for (int i=0; int <5; i++)

Here you use int instead of i for the run condition.

Function(int v1, int v2, i)

Here you declare v1 and v2, but they are undefined (they have a unknown value). Declare and initialize them before the loop. Also no semicolon at the end.

A function within a loop, with unchanged arguments

3 Answers3