Programming Help! (C++)

[TMRNetShark]

Hello everyone, I need some help getting a program started (not really written for me, but more of a guideline of how to set it up). Here are the instructions..

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1) Declare an integer x and initialize x to 5.
2) Declare a pointer to an integer px and initialize px to the address of x.
3) Use the pointer px to add 2 to x (indirect reference).  The value of x should now be 7.
4) Use the pointer px to display the value of x (indirect reference).
 
In steps 3 and 4 above, make sure your program uses the pointer px (indirect reference) rather than using the integer x (direct reference).

I do not know how to set up or do 3-4 to work properly. Any help would be great!

[Garret02]

I think it should be like this

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int x = 5;
int *px;
px = &x;
*px += 2;
cout<<*px<<endl;

[TMRNetShark]

I think it should be like this

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int x = 5;
int *px;
px = &x;
*px += 2;
cout<<*px<<endl;

Now I can use this all under main, correct? No global variables or other functions, correct?

[Garret02]

Yup, but remember to use either std:: before every cout and cin or type "using namespace std;" outside any function.

[Freedom Kira]

That's pretty much right, though I would use

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int *px = &x;

instead of

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int *px;
px = &x;

because I'm lazy. And you should be, too. Save yourself as much typing as possible - it'll decrease the chance of bugs.

And you can put this code anywhere, though parts 3 and 4 won't work so well in the global domain.

The "using namespace std;" should come once in every .cpp file below all your includes (unsure of exact include syntax because different languages use different include syntax). For example:

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#include iostream
using namespace std;

int main(void)
...

void function1(char x)
...

And for beginner-level C++, you should be putting the "using namespace std;" in pretty much every .cpp file.

[xShadow]

A function that just takes in a character? Interesting. Well, maybe if you had something that printed out the character input into some kind of image file via a predefined array of places to paint, and randomized colors (though you'd likely want an X/Y offset for that).

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I just finished up yet another class that solely focused on C programming (not C++; for some reason us computer engineers need hardcore C coding skillz). Well, actually, no, for the first few weeks we also converted our C code to assembly (that was fun! 20 lines -> 300 lines... but that was a bad code; it worked though).

I noticed that C++ has a few differences from C. Namely, that "cout" command. Is that another way to do "printf("%d",x)"? I've quite honestly never used that.

I've also never seen that "namespace". According to what I've read it's... kind of like using a .h file with declarations to things you want to use? Kinda confused here. That's kind of weird, what's the advantage of it to a header file?

Anyway, C++ seems to have some interesting stuff. I'll prolly be watching this thread because I wanna learn a bit more about what you can do differently in it, just for the heck of it (if the TC continues to ask questions here).

[TMRNetShark]

A function that just takes in a character? Interesting. Well, maybe if you had something that printed out the character input into some kind of image file via a predefined array of places to paint, and randomized colors (though you'd likely want an X/Y offset for that).

(click to show/hide)

I just finished up yet another class that solely focused on C programming (not C++; for some reason us computer engineers need hardcore C coding skillz). Well, actually, no, for the first few weeks we also converted our C code to assembly (that was fun! 20 lines -> 300 lines... but that was a bad code; it worked though).

I noticed that C++ has a few differences from C. Namely, that "cout" command. Is that another way to do "printf("%d",x)"? I've quite honestly never used that.

I've also never seen that "namespace". According to what I've read it's... kind of like using a .h file with declarations to things you want to use? Kinda confused here. That's kind of weird, what's the advantage of it to a header file?

Anyway, C++ seems to have some interesting stuff. I'll prolly be watching this thread because I wanna learn a bit more about what you can do differently in it, just for the heck of it (if the TC continues to ask questions here).

Dude, it's an elective class, I don't care about it... I can never understand why people want to do this as a job. It's just an hour of listening to the really good teacher... well... teach. Then 5 hours of banging my head against something because of goddamn errors. hahah

[Freedom Kira]

Meh, if you're good at it, you're good at it. It pays good too.

A function that just takes in a character? Interesting.

Sure. A function can take in anything. It was just an example anyway.

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I just finished up yet another class that solely focused on C programming (not C++; for some reason us computer engineers need hardcore C coding skillz). Well, actually, no, for the first few weeks we also converted our C code to assembly (that was fun! 20 lines -> 300 lines... but that was a bad code; it worked though).

I noticed that C++ has a few differences from C. Namely, that "cout" command. Is that another way to do "printf("%d",x)"? I've quite honestly never used that.

I've also never seen that "namespace". According to what I've read it's... kind of like using a .h file with declarations to things you want to use? Kinda confused here. That's kind of weird, what's the advantage of it to a header file?

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C is actually one of the most versatile (and probably the most powerful, in terms of ability) languages in existence. Modern OS's, including pretty much every Linux kernel in existence, and Windows, are built on C. C++ is a simple derivative of C that is heavily object-oriented. C programming is, however, considerably more difficult. Memory leaks and segmentation faults are the most common and frustrating problems you will encounter when programming in C.

Since OP is taking this as a tech elective, he's probably not going to be using most of the object-oriented features of C++. Which is unfortunate, because object-orientation is the whole point of C++.

cin/cout are easily my favorite C++ keywords. It just pipes shit to stdout. So yes,

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cout << x << endl;

does the same thing as

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printf("%d\n", x);

but is far simpler to type. (endl is "end line")

Note you can still use all your standard C functions like printf in C++.

Namespaces are a bit different from header files. You can #include header files as you do in C, with slightly different syntax.

A namespace is a predefined library of functions you can use. If you know any Java, "using namespace std" would be like "import java.lang.*" or something. The latter is not necessary to explicitly put into code, though.

Namespaces are specific to object-oriented languages like C++ and C#. Java uses what are called libraries that are pretty much the same thing.