C++ endl with constants

Question

I am just trying to familiarise myself with the basics of C++ moving from Java. I just wrote this functionality abstinent program and am coming across an errortest.cpp:15: error: expected primary-expression before ‘<<’ token and I am not sure why.

Anybody care to explain why endl is not working with constants? The code is below.

//Includes to provide functionality.
#include <iostream>

//Uses the standard namespace.
using namespace std;

//Define constants.
#define STRING "C++ is working on this machine usig the GCC/G++ compiler";

//Main function.
int main()
{
  string enteredString;

  cout << STRING << endl;
  cout << "Please enter a String:" << endl;
  cin >> enteredString;
  cout << "Your String was:" << endl;
  cout << enteredString << endl;

  return(0);
}

The snippet above does have this: `#include `. Does your original code have it? — yasouser, Jul 11 '11 at 20:41

score 8 · Answer 1 · answered Jul 11 '11 at 20:42

8

Your #define has a semicolon at the end. That becomes part of the macro, so the pre-processed code looks like this:

cout << "C++ is working on this machine usig the GCC/G++ compiler"; << endl;

Remove the semicolon and you should be fine.

PS: It's usually a better idea to use real constants for this rather than relying on the preprocessor:

const char *STRING = "C++ is working on this machine usig the GCC/G++ compiler";

answered Jul 11 '11 at 20:42

hammar

138,522
17
304
385

1

he also needs to include for "string enteredString;" to compile – Pepe Jul 11 '11 at 20:44
@Peter: actually many implementations of `` will include it for you. – KillianDS Jul 11 '11 at 20:46
@KillianDS: You shouldn't rely on that for portable code, though. – hammar Jul 11 '11 at 20:47

score 6 · Accepted Answer · answered Jul 11 '11 at 20:43

6

You have a ; in your preprocessor definition. Note that #DEFINE STRING x just copies the whole x-statement (including the ;) into the place where it's referenced.

Also, a preprocessor constant isn't a language constant. You should use const string STRING("C++ is working on this machine usig the GCC/G++ compiler");

answered Jul 11 '11 at 20:43

KillianDS

16,936
4
61
70

Ah ok, that makes sense, rookie error. Oh, would you happen to know why only the first word of my string is printed? Thanks. – Jack H Jul 11 '11 at 20:50
1

@VisionIncision: `cin >> enteredString` only reads one word. To read the whole line use `getline(cin, enteredString)`. – hammar Jul 11 '11 at 20:52

score 2 · Answer 3 · answered Jul 11 '11 at 20:43

2

You've got a secmi-colon at the end of your #define - this will be substituted into your code, giving.

cout << "C++ is working on this machine usig the GCC/G++ compiler"; << endl;

answered Jul 11 '11 at 20:43

Node

3,443
16
18

score 1 · Answer 4 · answered Jul 11 '11 at 20:42

1

Because you have a semi colon after STRING. Remove it and give it a try...

answered Jul 11 '11 at 20:42

Leandro T. C. Melo

3,974
22
22

score 1 · Answer 5 · answered Jul 11 '11 at 20:43

1

Remove the ; in the STRINGS definition

answered Jul 11 '11 at 20:43

littleadv

20,100
2
36
50

score 1 · Answer 6 · answered Jul 11 '11 at 20:43

1

Remove ; from

#define STRING "C++ is working on this machine usig the GCC/G++ compiler"

answered Jul 11 '11 at 20:43

Bruno Alano

643
1
11
21

score 1 · Answer 7 · answered Jul 11 '11 at 20:43

1

Remove the ; at the end of #define STRING and try again.

answered Jul 11 '11 at 20:43

yasouser

5,113
2
27
41

score 0 · Answer 8 · edited Jun 20 '20 at 09:12

0

define is a preprocessor directive. This replaces everything that follows the defined macro, in this case STRING. So, remove the last semicolon (;) that puts an end-of-statement marker while being expanded in the offending line.

edited Jun 20 '20 at 09:12

Community

1
1

answered Apr 04 '14 at 11:09

Dr. Debasish Jana

6,980
4
30
69

C++ endl with constants

8 Answers8

define is a preprocessor directive. This replaces everything that follows the defined macro, in this case STRING. So, remove the last semicolon (;) that puts an end-of-statement marker while being expanded in the offending line.