Thread: Which code is better?

Hello all,

Which of the following code is better? Please tell me on what your answer is based, convention, understand-ability or usability.

First one:

package Java24;
 
public class HR9StudentGrades {
	public static void main(String []args){
        //Hour nine, activity one.
        int twodim [][] = new int[6][6];
 
        twodim[0][0] = 30;
        twodim[0][1] = 26;
        twodim[0][2] = 88;
        twodim[0][3] = 96;
        twodim[0][4] = 72;
        twodim[0][5] = 81; 
 
        int SIX = 6;
        int issac = 0;
 
        for(int index = 0; index < 6; index++){
            issac = issac + twodim[0][index];
        }
        issac = issac / SIX;
        System.out.println("The average grade mark of Issac is: " + issac);        
    }
}

Second One:

package Java24;
 
public class TestFile {
	public static void main(String []args){
        //Hour nine, activity one.
        int twodim [][] = new int[6][6];
 
        twodim[0][0] = 30;
        twodim[0][1] = 26;
        twodim[0][2] = 88;
        twodim[0][3] = 96;
        twodim[0][4] = 72;
        twodim[0][5] = 81;
 
        int SIX = 6;
        int issac = 0;
 
        for(int index = 0; index < 6; index++){
            issac = issac + twodim[0][index];
            if(index == 5){
            	issac = issac /SIX;
            	System.out.println("The average grade mark of Issac is: " + issac);
            }
        }
    }
}

I only pasted part of the, if you want the full code let me know.

Thanks for taking time to answer!
-Alem

Edit:
Only diffidence atm is the for loop.

Unless SIX can hold a value other than 6, I would just get rid of it and use 6 in your code.

If it can hold another value, call it by what it's used for (for example, call it numGrades). Same thing goes for twodim: it look like it's used to store the grades of the students, call it something that reflects that.

Also, I would recommend against hard-coding variable names for the people. It's much more difficult to add new names.

The best way to accomplish all of these tasks is to create a Student class which contains the student's name and 6 grades (actually, use an array to get an arbitrary number of grades). It could have methods for computing the student's average grade, and getter methods for the student's name and individual grades if necessary. Then in your main method, just have an array of Student objects. Loop through the array and print out the necessary information for each student.

Also, I would recommend against hard-coding variable names for the people. It's much more difficult to add new names.

A bit con fuddled there, could you explain a lil more please?

This:

        int issac = 0;
        int dawiet = 0;
        int alem = 0;
        int ghebremariam = 0;
        int daniel = 0;
        int minus = 0;

because that causes this:

        for(int index = 0; index < 6; index++){
            issac = issac + twodim[0][index];
        }
        issac = issac / SIX;
        System.out.println("The average grade mark of Issac is: " + issac);
 
        for(int index = 0; index < 6; index++){
            dawiet = dawiet + twodim[1][index];
        }
        dawiet = dawiet / SIX;
        System.out.println("The average grade mark of dawiet is: " + dawiet);
 
        for(int index = 0; index < 6; index++){
            alem = alem + twodim[2][index];
        }
        alem = alem / SIX;
        System.out.println("The average grade mark of alem is: " + alem);
 
        for(int index = 0; index < 6; index++){
            ghebremariam = ghebremariam + twodim[3][index];
        }
        ghebremariam = ghebremariam / SIX;
        System.out.println("The average grade mark of ghebremariam is: " + ghebremariam);
 
        for(int index = 0; index < 6; index++){
            daniel = daniel + twodim[4][index];
        }
        daniel = daniel / SIX;
        System.out.println("The average grade mark of daniel is: " + daniel);
 
        for(int index = 0; index < 6; index++){
            minus = minus + twodim[5][index];
        }
        minus = minus / SIX;
        System.out.println("The average grade mark of minus is: " + minus);

You have a ton of loops which basically do the same thing for different variables, but exponentially increases the amount of code you need to maintain.

In conjunction with creating a Student object (or if you really don't want to go down that path for some obscure reason), use arrays and just refer to them as "students" or something like that. Arrays are nice because you can easily loop through them.

To further reinforce this, use the length field of the arrays whenever possible. It's a very big pain to have to hard-code the size of the array.

// solution if you didn't create a student object
String[] studentNames = new String[]{"issac", "dawiet", "alem", "ghebremariam", "daniel", "minus"};
int[] studentAverages = new int[studentNames.length];
int[][] studentScores = new int[studentNames.length][6];
// ...populate studentScores with the respective students' scores
 
// ... later on, when computing averages:
// I know I said use descriptive names, but I got a little lazy and it's fairly well understood that i and j are indices
for(int i = 0; i < studentNames.length; ++i)
{
    for(int j = 0; index < studentScores[i].length; ++index)
    {
        studentAverages[i] += studentScores[j][index];
    }
    studentAverages[i] /= studentScores[i].length;
    System.out.println(studentNames[i] + " average score: " + studentAverages[i]);
}

Further improvements (other than the obvious one of using a Student object) would be to abstract away the average calculation to a "helper method".

for(int i = 0; i < studentNames.length; ++i)
{
    studentAverages[i] = computeAverage(studentScores[i]); // computeAverage is a method which takes in an array of scores and computes their average
    System.out.println(studentNames[i] + " average score: " + studentAverages[i]);
}