C++ comma operator

Question

I'm trying to run this code from C++ Primer plus

#include <iostream>
using namespace std;

int main() {
    int i = 20, j= 2*i;
    cout << "i = " << i << endl;
    int cats = 17,240;  //No, I don't want the number 17240
    return 0;
}

Why I'm seeing this error expected unqualified-id before numeric constant int cats = 17,240; , I don't know, I need a short explanation. Thanks

Just remove the `,`. `int cats = 17240;` – pingul Feb 21 '17 at 13:54 — pingul, Feb 21 '17 at 13:54
what are you trying exactly with 17,240? – Adrian Maire Feb 21 '17 at 13:54 — Adrian Maire, Feb 21 '17 at 13:54

score 2 · Accepted Answer · answered Feb 21 '17 at 13:55

2

int cats = 17,240; would be viewed by the compiler as int (cats = 17),240; due to operator precedence. And int 240; makes no sense, so a compiler diagnostic is issued.

Did you want 17240 cats? If so then drop the comma.

answered Feb 21 '17 at 13:55

Bathsheba

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Please see the link to book. I'm just trying to run exactly the lines written in the book under heading "Comma operator Tidbits" (link is in the question). – Feb 21 '17 at 13:59
1

@DeepChandra: Don't include links like that in questions. They can be brittle and your particular one is not valid in certain jurisdictions. – Bathsheba Feb 21 '17 at 14:00

C++ comma operator

1 Answers1