Thread: What Is The Purpose Of This Piece Of Code

This is a exercise to practice desk checking so dont say to run it.
I cant follow through the loops
can someone please help me



import javax.swing.JOptionPane;
public class Main {
public static void main(String[] args) {
int values[] = new int[5];
int z;
for (int i = 0; i<5; i++){
values[i]=Integer.parseInt(JOptionPane.showInputDialog("Ent er Int
value"));
}
for (int p = 0; p<4; p++){
for (int q=(p+1); q<5; q++) {
if (values[q]<values[p]){
z=values[q];
values[q]=values[p];
values[p]=z;
}
}
}
for (int i = 0; i<5; i++){
System.out.println(values[i]);
}
}
}


Presuming that you have identified the purpose of the above code, and how its algorithm operates, write a brief specification of the method.
Now assume that you are an independent tester of software, and have only been given the specification of that method, and that you have to “fully” test it as an independent method.
Could you think of a set of test cases (i.e. more than just one) which you would need to develop to
do this? Key to developing a set of test cases is to think of any “special cases” of the input data which might not be “picked up” due to “slight” errors in the development of the algorithm used by the programmer.

Get out a piece of paper and write down all the variables and their values, Step through each step slowly and write down the values accordingly. That's the best way to do a desk check.

i cant seem to follow the loop through would you be able to help me

take each piece one at a time.

Ill help you get started

int values[] = new int[5];
		int z;
		for (int i = 0; i<5; i++){
			values[i]=Integer.parseInt(JOptionPane.showInputDialog("Ent er Int value"));
		}

This allows the user to enter in 5 integers into an array.

for (int p = 0; p<4; p++){   // this loop goes 4 times
			for (int q=(p+1); q<5; q++) {   //this loop goes 4 times
				if (values[q]<values[p]){     
					z=values[q];             //temp variable used for swapping. HINT: swapping involves sorting.
					values[q]=values[p];
					values[p]=z;
				}
			}
		}

i knew that the first part asks for them to enter 5 numbers and puts them into the arrays its the next part that i cant follow as i dont really know where to start

Do what Norm suggested, write down the values each time through the loop and post what you think they are here.

i only have the values when it asks the user to enter values and puts them in the array as i cant seem to follow the loops. the values i have there are 7, 4, 10, 1 ,19

Do you know how for loops work?

Look into nested loops . The inner code of the outter loop will go (inner loop * outter loop) times.

where would i start. with the if statement then work out to the inner for then the outer?

https://www.youtube.com/watch?v=ZcTgmKtvSQ4

This will help explain nested loops better.

You're going to want to start with the first loop, then the second loop, then the if statement.

@amb101293: Welcome to the forum! Please read this topic to learn how to post code in code or highlight tags and other useful info for new members.

in the if statement where does the values[q] and values [p] come from

they are the values that you put in. q and p are just the indexes. So if you have an array that you put 5 integers in say they were

values = 2, 90, 6, 100, 8

and value of q is 0, Then values[q] is the same as saying values[0], which in turn is 2.

the code that i posted is the only code i have for this question

p - 0
q - 1
values[p] - 7
values[q] - 12

would the final answer after the loops have ran all 4 times that the array is as follows if the 5 values entered is : 7, 12, 2, 10, 21

would the answer be

7, 2, 10, 12, 21

Not quite, you're getting closer though.

This is what i got well at the end of the for, for And if loop is that correct before I go on to do the last bit