Thread: New to C++

So, recently deciding that I want try and learn C++, I picked up "Teach Yourself C++ in 24 Hours" for a starting point. All works well, until Hour 2 ( ) where I come to a problem - I type in the code exactly as it is in the book, compile it, and when I run the program, the output is different than what is shown in the book.

Here is the code:

Code:

#include <iostream>

int Add (int x, int y)
{
	std::cout << "In Add(), recieved " << x << " and " << y << "\n";
	return (x+y);
}

int main()
{
	std::cout << "I'm in main()!\n";
	std::cout << "\nCalling Add() \n";
	std::cout << "The value returned is: " << Add(3,4);
	std::cout << "\nBack in main().\n";
	std::cout << "\nExiting...\n\n";
	return 0;
}

Here is what is supposed to come out:
I'm in main()!

Calling Add()
In Add(), received 3 and 4
The value returned is: 7
Back in main().

Exiting...

And, finally, here is what I get:
Calling Add()
The value returned is: In Add(), received 3 and 4
7
Back in main().

Exiting...

A few notes - I use Mac OS X 10.4.6, write the code in Xcode, and use the Terminal to compile. I thought maybe the output was different because I am running OS X, but that does not make any sense to me. I have read the code over and over, just to make sure I typed everything correctly.

Sorry for the long post, and not sure if I broke any rules by posting code on here, if I did, just left me know. Any help at all on this issue would be greatly appreciated!

Thanks,
~eros

My output was

I'm in main()!

Calling Add()
In Add(), received 3

Im running Windows and copyed and pasted the code in Dev C++. I dont know why your having a different output 2 mine

> std::cout << "The value returned is: " << Add(3,4);
Welcome to the world of side effects.

Your book shows one plausable answer - the function is called first, then the string and result is printed.

Your compiler shows another plausable answer - the first string is printed, then the function is called and then the result printed.

Neither is right or wrong. If the Add() function didn't call cout, it would not matter which order things were done in.

To guarantee the order, you would need to do this

Code:

int answer = Add(3,4);
std::cout << "The value returned is: " << answer;

> Sorry for the long post
Not a problem - I regard this as a model post.
It's got
- the question
- the code
- the output
- the OS
- the compiler
perfect IMO.

It's a lot better than many of the cryptic "plz hlp" illiterati who post one line of code and no information as to what they have, what they see etc etc.

Originally Posted by Hugo716

Hmmm, whats the std:: for?

u dont need to use std:: u can just use cout <<" "

Only if you declare the using preprocessor (using namespace std;), which he isn't doing. There are reason's not to use it, and use std:: instead, but the purpose isn't relevent until further than intermediate stages.