CodeGym/Help with Java Tasks/The task work well, but the verifier give me 3*RED

Level 23

Szekesfehervar

16.02.2020
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28comments

The task work well, but the verifier give me 3*RED

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Hi, i think, my solution to "Multiplication table" task works well. The table is displayed, it contains 10 lines, and the numbers are right. I used the "for" cycle. But the task-verifier said the follows: The program should output text. - GREEN The displayed text should contain 10 lines. - RED Each displayed string must contain 10 numbers separated by spaces. - RED The displayed numbers must form a multiplication table. - RED I don't understand why! - - - - - - - - - - - - But, i made an other version, see below. I converted the numbers in one line into one string, and these lines doesn't contain space at the end of the lines, but the task-verifier says the same!:-/ public class Solution { static int a=1; static int b=1; static String resultText = ""; static int result; public static void product() { for(; b<11; b++) { resultinOneLine(); } } public static void resultinOneLine(){ for(; a<11; a++){ result = (a*b); resultText= resultText + Integer.toString(result); if (a<10) { resultText += " "; } else { } } System.out.println(resultText); a=1; resultText = ""; } public static void main (String[] args){ product(); } }

package com.codegym.task.task03.task0314; /* Multiplication table */ public class Solution { static int a=1; static int b=1; public static void product() { for(; b<11; b++) { resultinOneLine(); System.out.println(""); } } public static void resultinOneLine(){ for(; a<11; a++){ System.out.print(a*b + " "); } a=1; } public static void main (String[] args){ product(); } }

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giuse

Level 8 , Turin, Italy

31 March 2020, 22:47

Try something like it: for(int i = 1; i <= 10; i++){ for(int j = 1; j <= 10; j++){ System.out.print((j * i) + " "); } System.out.println(); }

Gellert Varga

Level 23 , Szekesfehervar, Hungary

31 March 2020, 23:11

Thanks, but my problem is resolved already:)

Pablo Saquilmer

Level 32 , Guatemala City, Guatemala

10 March 2020, 18:47

Why is not showing to me the requirements???

Gellert Varga

Level 23 , Szekesfehervar, Hungary

11 March 2020, 11:44

If you mean why IDEA don't show the task-requirements, then try to do this: On the left side of IDEA push the "CodeGymPlugin.properties". And on the right side, write this in a new line (under the other code lines): codegym.html.disable=true NO space, NO quotation mark, NO enter! Just write it in there. (The CodeGym support explained this to me.)

Guadalupe Gagnon

Level 37 , Tampa, United States

28 February 2020, 14:48

solution

You should not use static variables. It is generally poor practice to do so unless specifically needed, and a lot of tasks will automatically fail if you do use them. You should be able to pass this task by removing the static variables and using a while loop like JAKUB pointed out.

Gellert Varga

Level 23 , Szekesfehervar, Hungary

28 February 2020, 20:31

OK. According to your advice, i transformed my program. So the verifier finally accepted my solution. Thank you very much for the practical advices! I will heed these hereafter. (But i still don't understand, why the verifier don't accept an other solution if it works and meets the requirements.)

Guadalupe Gagnon

Level 37 , Tampa, United States

28 February 2020, 20:51

useful

I couldn't say why the validation system doesn't accept some solutions, i am not sure how it is coded and the algorithm used to take your code and pump in test values. Just remember to stay away from static variables in this course unless they specifically say to use or add them. I was failing a lot of tasks too when I was leveling up because of this.

Gellert Varga

Level 23 , Szekesfehervar, Hungary

28 February 2020, 21:18

To stay away from static variables - but just in this CodeGym-course? Otherwise, no problem with them? (I thought this was a general truth.)

Guadalupe Gagnon

Level 37 , Tampa, United States

29 February 2020, 20:51

useful

There is no problem with them. It is just generally poor deign to just use them wherever. It is better to use local variables and pass values around using method arguments. There are plenty of reasons why you would use them though, take something like a game where there is a player score. You can gain score by doing multiple different things, it wouldn't make sense to use a local variable there but a class variable (static).

Gellert Varga

Level 23 , Szekesfehervar, Hungary

1 March 2020, 11:32

Thank you very much! It made this subject very clear. -- Maybe, if you have some time, can I bother you with another questions, too? I have some unanswered comments below the lectures that are not related to any concrete task, so I can't post it to the help section. So I don't know who to ask these questions from.

Guadalupe Gagnon

Level 37 , Tampa, United States

1 March 2020, 16:12

Feel free to ask any questions. I'll answer the best I can when I see them.

Gellert Varga

Level 23 , Szekesfehervar, Hungary

14 March 2020, 15:20

Hi! Thanks!! I have a little confusion. I just tried to write a little program, what - accepts int-s from keyboard one after the other, and displays them ((or does something with them)), - if you typed something else in, not an int, then displays "False input, try again!", and waits for more int-s, - and quits, if you typed "exit". In the program i used : - the Scanner(System.in) to read the inputs, - hasNextInt() method, to select the type of inputs (int or no), - and the string.equals("exit") method to determine to quit or no. The program works viewed in the large, but sometimes it makes strange effects. - For example, sometimes the entering input "while" loop runs twice and it displays the "False input, try again" string twice. But sometimes only once! - And when i type in the "exit", sometimes displays the "False input, try again" before quit, sometimes not (but it never should). I thought a lot about it, but I can't figure out why. If you have time for this, may i send you this little program, and would you look at it what's wrong with it?

Guadalupe Gagnon

Level 37 , Tampa, United States

14 March 2020, 17:45

It sounds like the program should be reading in strings instead of ints so that it can test for the word "exit" before it tests if the input is a valid number.

JAKUB

Level 4 , Łódź, Poland

16 February 2020, 15:18

well, everything should work correctly, output is fine, but in task description is "Here's your secret weapon: the while loop." sooo, maybe this is the problem?

Gellert Varga

Level 23 , Szekesfehervar, Hungary

16 February 2020, 17:29

Ok, thanks! I didn't notice that. I was just looking at the "conditions" window, and this criterion wasn't listed there.

JAKUB

Level 4 , Łódź, Poland

16 February 2020, 18:33

worked?

Gellert Varga

Level 23 , Szekesfehervar, Hungary

16 February 2020, 21:38

i will try it later

Gellert Varga

Level 23 , Szekesfehervar, Hungary

28 February 2020, 14:38

I solved this task with the cycle "while", too. The output was the right multiplication, too. And the the verifier gave me 3*RED again, too...

JAKUB

Level 4 , Łódź, Poland

9 March 2020, 21:26

how your code looks like?

JAKUB

Level 4 , Łódź, Poland

10 March 2020, 20:55

great, and thanks to this I was able to complete couple tasks i couldn't finish - all of them had static variables well - thanks and good luck on the next!

Gellert Varga

Level 23 , Szekesfehervar, Hungary

11 March 2020, 12:04

Thanks and same to you! - I don't know, why the requirements don't say: "Don't use static variables!" I was angry at this.:)

Jack

Level 4 , Yerevan, Armenia

21 April 2020, 18:37

Hey, Gellert Varga i didnt understand these lines - 1 b++; 2 } 3 System.out.println(""); 4 b = 1; 5 a++; on line 1 why only b++ on line 4 and 5 didnt understand can you please explain?

Gellert Varga

Level 23 , Szekesfehervar, Hungary

21 April 2020, 19:20

Hi Jack! b++; // it means: b=b+1; Line 5 is similar. (But what is this small part? If you will send me the whole program, only then i can understand what is this. Maybe.)

Jack

Level 4 , Yerevan, Armenia

22 April 2020, 15:05

its from your comment (the programme) because i know that its doing x+1 i just dont understand why in that order

Gellert Varga

Level 23 , Szekesfehervar, Hungary

22 April 2020, 18:05

OK, I already understand the question. There is an internal cycle. In this cycle, I increase the value of the variable "b" by 1 each time. This performs the multiplication in the cycle: a*b, a*b, a*b, .... a*b. For example if a = 2: 2*1, 2*2, 2*3, .... 2*10. Line 2: end of this internal cycle. Line 3: after "2*10" the next number (3*...) must be printed on a new line. (Printing an empty string = line break). The "b" is now 10. Must be reset to 1. Because the next number (3) must first be multiplied by 1, then by 2, and so on. So: Line 4: b = 1; Line 5: This is part of the outer cycle. Here I set the value of the variable "a" from 2 to 3. Then the inner loop increments the value of the variable "b" by 1 again and again, so you do this: 3*1, 3*2, 3*3, .... 3*10.

Jack

Level 4 , Yerevan, Armenia

23 April 2020, 16:47

օօօօօհ i get it i never knew about the line break and one more question how does it know when to start the cycle all over again (after it reaches 10, to 0 out the a and b)

Gellert Varga

Level 23 , Szekesfehervar, Hungary

23 April 2020, 21:08

Jack

Level 4 , Yerevan, Armenia

26 April 2020, 09:18

wow, you made this yourself ?! P.S. tnx for the help, I've already passed the lessons of line break,escaping characters and input/output streams.