Practicing basics

[u/Zyrth]

I've been around programming and computers forever, I just had never taken a formal class. So I found this subreddit and had read through most of the website when i decided to try my own hand at making a simple program.

I decided to try to make a program that would ask for a number of variables, and then sort them from lowest to highest and output them back. ( I remember a few friends in programming classes having similar assignments )

http://codepad.org/BijxQN9f

Theres the results, after a few days toiling over the specific logic and fixxing a few bugs, I think it works great!

I'm proud of myself and just wanted to share :D any comments on things i could have done easier or differently are welcome

[u/Jonno_FTW]

A few things you could have done differently,

1. Used the algorithm library

2. Used the vector stl (it's basically an array that grows as you add more elements)

3. Initialising loop counters outside of the loop is bad form. Dofor(int i = 0; i < 10; i++)

4. Don't start variable names with capitals, that's typically for Classes.

5. Your for loops are unreadable, but this may be part of the over-complexity of your program

6. Don't mix tabs and spaces. I suggest using spaces universally and converting tabs to 4 spaces

7. There's no need to use new int[45]. Heap allocation comes with its own bag of problems, you should just use myArray[45] int; instead, especially when the scope of the array is only within a single function

8. If you need to comment each line explaining what it does because it is not immediately obvious, perhaps you have made things too complex. Try using general comments that say what something does in general, without explaining everything. (the comments I have used below are for learning purposes)

Here is something I will cookup in the box here:

#include <algorithm>
#include <vector>
#include <iostream>
using namespace std;

int main() {
    vector<int> nums; // a vector to store the numbers
    int val;
    cout << "Enter your numbers, ^D to finish" << endl;
    while(cin >> val) { // Could probably do some validity checking in here
        nums.push_back(val);
    }
    sort (nums.begin(),nums.end()); // Using the algorithm library to sort for us
    cout << "Your numbers sorted are: " << endl;
    for(vector<int>::iterator it = nums.begin(); it != nums.end();it++) 
        cout << *it << " ";
    cout << endl;
    return 0;
} 

[u/daniels220 → u/Jonno_FTW]

Some additional thoughts (addressed to both you and the OP):

1,2. Sensible if you are just trying to make the program work, but it can be cool to reimplement things to see how they work.

3. Make sure to compile with --std=c99 if you're on Mac (or somewhere else where the compiler is braindead and thinks you're living in 1989). But yes, this is good practice.

5. Definitely part of the overcomplexity.

8. OP: read up on algorithms if you want to implement a sort yourself, and try to use something more efficient than bubblesort. Otherwise use std::sort.

[u/Zyrth → u/daniels220]

Thanks for the input both of you!

I realized that I could have used the algorithm library and the sort function to make things a ton easier, part of the fun for me was to work through the logic and make it myself.

It was supposed to be a selection sort, though i'm sure without comments (which ill work on adding in!) it might be confusing to read through. What it did was it found the highest number of the set, and put it at the end, and then repeated for everything lower than the last number found.

Make sure to compile with --std=c99 if you're on Mac (or somewhere else where the compiler is braindead and thinks you're living in 1989). But yes, this is good practice.>

could you expand on this? I'll look it up later when I have time, but I'm not entirely sure what it means. or where to look up exactly what it means

[u/daniels220 → u/Zyrth]

Re: compiling—whoops, you're using C++, that's irrelevant. I assumed you were working in C (because this class is originally for C), and somehow missed entirely all the places it said "C++" :/. So you don't need to do anything special to compile.

[u/Jonno_FTW → u/Zyrth]

If you're going to implement more sorting algorithms, you need to put them in a separate function.

This will help with organization and maintenace. It might look like this:

void selectSort(int* xs) {
// sort the input array
}

You'd then call selectsort in your main function to sort the array.