Yet more C++ programing help...

[GT98]

Well only one more week left so don't have to worry about it after then

heres what I got:

//•     Declares, initializes, displays the contents of pointers to an int.*
//•     Assigns one pointer to another pointer.*
//•     Compares pointers for equality.*
//•     Implements an array of ints using pointer notation and displays array elements by  incrementing a pointer.
//•     Implements a C-string using pointer notation and displays result of incrementing its pointer.*
//•     Implements a function that is passed a pointer as an argument (use function prototype). Function definition displays string content using only pointers.
//•     Creates a dynamic array, assigns it values and displays its content,Using only pointer notation.
//MS Visual Studio Academic Edition

#include <iostream>
#include <stdlib.h>
#include <fstream>
using namespace std;

int main() {
     
     int i=10;
    int *j;

       j=&i;

       cout<<"\n ---------- Addresses of Variables --------- \n"<<endl;
       cout<<"Address of i = "<<&i<<endl;
       cout<<"Address of j = "<<&j<<endl;

       cout<<"\n ---------- Values of Variables -------- \n"<<endl;
       cout<<"value of i = "<<i<<endl;
       cout<<"value of j = "<<j<<endl;
       cout<<"value of *&i = "<<*&i<<endl;
       cout<<"value of *j = "<<*j<<endl;

       cout<<"\n *j = 5 \n"<<endl;
       *j=5;

       cout<<"value of *j after modification = "<<*j<<endl;


     cout  << boolalpha //compares pointers for equality
         << "The true expression 5 != 2 yields: "
         << (5 != 2) << endl
         << "The false expression 40 == 10 yields: "
         << (40 == 10) << endl;
     
   int *onePtr, *twoPtr, a = 10; //Assigning a pointer to another pointer
     onePtr = &a;
     *onePtr = 40;
     cout << a << endl; // outputs 40
     cout << *onePtr << endl; // outputs 40
     twoPtr = onePtr; // same as twoPtr = &a;
     cout << *twoPtr << endl; // outputs 40

     int i_array[MAX] = { 0,1,2,3,4,5,6,7,8,9 };
     int *i_ptr, count;
     float f_array[MAX] = { .0, .1, .2, .3, .4, .5, .6, .7, .8, .9 };
     float *f_ptr;
    i_ptr = i_array;
    f_ptr = f_array;
    for (count = 0; count < MAX; count++)
          printf("%d\t%f\n", *i_ptr++, *f_ptr++);

       
   return 0;
    }

I'm getting an error towards the end of the program saying I have too many identifiers and MAX is an undeclared identifier..can anyone help me out with this?

Also Can someone point me in the right direction to solving these?

Implements an array of ints using pointer notation and displays array elements by incrementing a pointer
Creates a dynamic array, assigns it values and displays its content,Using only pointer notation
Implements a function that is passed a pointer as an argument (use function prototype). Function definition displays string content using only pointers

Thanks!

[Jon P. Inghram]

You might try actually defining "MAX", as the compiler can't read minds.

#define MAX 10

or

const MAX = 10;

Not sure which is "better," because I don't really know C.

[gt40]

It's only been 15 yrs since my last foray into C++

[Wombat]

You might try actually defining "MAX", as the compiler can't read minds.

#define MAX 10

or

const MAX = 10;

Not sure which is "better," because I don't really know C.

The #define is better. You don't want to use any kind of variable for the declaration of an array that comes off the stack.

Also, off the cuff, I don't think you can declare the size of an array if you're defining its contents at the same time.

[Jon P. Inghram]

Also, off the cuff, I don't think you can declare the size of an array if you're defining its contents at the same time.

Just looked it up and you can do it either way.

GT98, you might try an online tutorial on C++, like http://www.cplusplus.com/doc/tutorial/ or http://www.cprogramming.com/

[KeiFront]

A const (static const) is always preferable it has a scope and a type, a define hasn't.

You can look at a define as a text replacement (the preprocessor does all the text replacement before the compiler compiles the code), you mainly use defines for macro's or in header files. Also a define (#ifdef #endif) can always be redefind afterwards so another reason to use a const.

[Wombat]

A const (static const) is always preferable it has a scope and a type, a define hasn't.

You can look at a define as a text replacement (the preprocessor does all the text replacement before the compiler compiles the code), you mainly use defines for macro's or in header files. Also a define (#ifdef #endif) can always be redefind afterwards so another reason to use a const.

On the contrary, you want a define precisely because of the reasons you've described. When you're keeping multiple arrays tied together, the global scope of a #define helps keep things in sync, across classes and cross-linked programs, and you can indeed prevent redefines much in the same way you prevent multiple inclusions - this prevents compilation much the same way that attempting to redefine consts does. Plus, what does the type of a const buy you in the context of an array size? Since standard C arrays cannot change size dynamically, textual substitution makes sense. In fact, the lack of a type may even be beneficial, as you can use the size of the array as a comparison against different types of variables (int, u8, u64, longs...) to see if you can manage the size of the array.

[KeiFront]

He's using C++ (and you can resize a C array with malloc iirc, my C is very rusty, I mainly programmed in C++), and you want to obey scoping rules so a const is preferable. Also you will learn to value type safety. A define can have nasty side-effects.

[Wombat]

Yeah, I'm aware of the risks, but in my line of work they're often well outweighed by benefits. I specifically would NOT WANT to limit the scope of the array size define - I want it to be visible so that different codebases could include the same defines.

Trying to malloc an array to resize it wouldn't work. It's just a new array, somewhere else, with unknown default values. C++ arrays aren't resizable either that I'm aware of, unless you're using an STL class, and you'd probably want a vector anyway at that point.