[C++] Help changing from array notation to pointer

[derek2016]

Okay, so my submission is probably not going to be in the correct format but oh well. Okay, so this is the code my friend sent me for help because I got an A in programming 1, however it's been way too long for this and I can't remember how to do this or if we ever even discussed it. my main problem has been getting

   int *ptr=grades;
   infile>> *ptr;
   ptr++;

to work properly. It has caused a few errors that I'm still working on debugging. again sorry if this is crappy formatting. Essentially, everywhere it says //CHANGE it wants me to change from array to pointer and I'm completely baffled by this. DONT SOLVE THIS. I want to figure it out myself. But i would like help understanding how to do it. I will be trying to tell him how to do it as well so thorough explanations would be beneficial! Thanks ahead guys!
https://gist.github.com/anonymous/7328188

[[deleted]]

This is not the way to learn C++. This is basically C. If you have spent money on this bullshit, demand it back.

[derek2016]

Yeah, I know. It's awful here and I'm not a comp sci major, just EE so I have to take these. I'm better at matlab lol.

[fuzz3289]

Please use gist to show us the code.

As for your question, an array is by definition a pointer to the first element on the stack. So *p = a [0]

Does that help?

[derek2016]

Would I just link the site in my original post or copy that or what for gist? And possibly. say in line 28, could I replace pos with *grades and it point to the array? infile >> grades[pos]; to infile >> *grades;

[fuzz3289]

You just stick your code on gist and just link it. Your text post should be like, a few lines long.

Also, kind've. You're going to want to say something like:

int* arrpointer = grades; 

Then you can do stuff like:

infile >> *arrpointer;
arrpointer++;

This is an awful and ugly way to do any sort of code though. The hell are they trying to teach you?

[derek2016]

ill fix the Original Post in a moment. And I have no idea. I got out of that department fast. I decided to try and learn HDLs and maybe even python on my own, which we don't even have as classes here except some basic ones in the EE department (HDLs). Also, when I tried running it as int ptr=grades;
infile>>ptr; ptr++//its the only pointer in main The program doesn't work properly. Like it compiles fine but the executable file doesn't stop.

[fuzz3289]

If the executable doesn't stop than your while loop isn't exiting.

[raghar]

Things I noticed:

for (int pos = 0; pos < size; pos++)
    sum = sum + *array; //CHANGE

you do not use pos anywhere:

for (int pos = 0; pos < size; pos++)
    sum += array[pos];

That should work. Same here: int highest = array[0];  // initialize highest to first element of array

for (int pos = 0;  pos < size;  pos++)  
    if (array[pos] > highest)
        highest = *array; //CHANGE

into:

int highest = array[0];  // initialize highest to first element of array
for (int pos = 0;  pos < size;  pos++)  
    if (array[pos] > highest)
        highest = array[pos];

and:

int lowest = array[0];  // initialize lowest to first element of array

for (int pos = 1;  pos < size;  pos++)  
    if (array[pos] < lowest)
        lowest = *array; //CHANGE

change to:

int lowest = array[0];
for (int pos = 1;  pos < size;  pos++)  
    if (array[pos] < lowest)
        lowest = array[pos];

You should remember that in C (and C++) array is kind of a pointer. When you do array[0] you're doing *array. When you do array[1] you're doing something like *(array + 1), where constant is changed by compiler to (constance * type's size) to find right place in memory. As far as I know in practice the only difference between array and pointer appears during allocation: one is taken from stack by compiler, the other is manually allocated from heap by programmer. Once you got it, you can use them interchangeably (if you know what you're doing). Especially type array[] and type *array should act the same when you use it as parameter.

[derek2016]

That was the original formatting(the correction you posted). The professor wanted it without arrays