get the figure using nested for loops in Java

Question

Any ideas how to write Java program in a class named Window that produces the preceding figure as output. I have to use nested for loops to print the repeated parts of the figure. I've tried lots of times, no success :(

Write a Java program in a class named Window that produces the preceding figure as output. Use nested for loops to print the repeated parts of the figure. Once you get it to work, add one class constant to your program so that the size of the figure can be changed simply by changing that constant's value. The example output shown is at a constant size of 3, but if you change the constant, the figure should grow larger and wider proportionally.

+===+===+
|   |   |
|   |   |
|   |   |
+===+===+
|   |   |
|   |   |
|   |   |
+===+===+

OK i've got this, but still need to get rid of 3 bottom lines - any idea?

    for (int i = 1; i <= 3; i++) {
        for (int plus = 1; plus <= 2; plus++) {
            System.out.print("+");
        for (int shave = 1; shave <= 3; shave++) {
                System.out.print("=");
            }
            }
        System.out.print("+");
            System.out.println();
    for (int time = 1; time <= 3; time++) {
         for (int kav = 1; kav <= 3; kav++) {
                 System.out.print("|");
             for (int rev = 1; rev <= 3; rev++) {
                 System.out.print(" ");
             }
             }
         System.out.println();
        }
    }

}

for (int line = 1; line <= 9; line ++) { for (int plus = 1; plus <= 3; plus++) { System.out.print("+"); for (int eq = 1; eq <= 6; eq++) { System.out.print("="); for (int k = 1; k <= 3; k++) { System.out.print("|"); } } } — alya, Feb 04 '12 at 22:49
Edit the code into your post, and point out what, exactly, the problem is. — millimoose, Feb 04 '12 at 22:57
This is a stupid homework assignment. When would this ever be useful? — Jivings, Feb 04 '12 at 22:59
@Jivings it is perfectly valid to ask about homework here as long as it conforms to the guidelines. — Thorbjørn Ravn Andersen, Feb 04 '12 at 23:01
@ThorbjørnRavnAndersen That wasn't what I was saying. I was implying that it's a stupid homework assignment to give out. — Jivings, Feb 04 '12 at 23:05
I think that teacher you have should definetely try to find better examples/exercises for teaching nested loops. This one is just too weird/useless... — Radu Murzea, Feb 04 '12 at 23:05
Well, it's not a teacher's assignment, I'm using this source http://webster.cs.washington.edu:8080/practiceit/problem.jsp?category=Building+Java+Programs%2C+2nd+edition%2FChapter+2&problem=2-e19-Window to practice more in Java — alya, Feb 04 '12 at 23:15
@Jivings, if it is hard, then perhaps it is not _so_ stupid? — Thorbjørn Ravn Andersen, Feb 04 '12 at 23:21
Easy ;-) `for(int i=0;i<1;) for(;i++<1;) System.out.print("+===+===+\n| | |\n| | |\n| | |\n+===+===+\n| | |\n| | |\n| | |\n+===+===+");` — JRL, Feb 04 '12 at 23:33
@ThorbjørnRavnAndersen I see no practical use for this kind of exercise. — Jivings, Feb 05 '12 at 09:41

Johnydep · Answer 1 · 2012-02-05T23:26:04.603

I think this is what you are Looking for:

        final int BLOCK_SIZE = 2;
        for(int i=0; i<1; i++){
            System.out.print("+===+");
            for(int j=0; j<1; j++){
                System.out.println("===+");
                for(int k=0; k<BLOCK_SIZE; k++){
                    System.out.println("|   |   |\n|   |   |\n|   |   |");
                    for(int l=0; l<1; l++){
                        System.out.println("+===+===+");
                    }
                } System.out.println();
            }
        }

banjoSas · Answer 2 · 2013-04-12T16:50:02.050

I was going through random questions and I found no one actually answered correctly by correcting the code you posted. So here I post my code with nested for loops and it satisfies all your criteria, giving the correct output.

int BLOCK_SIZE = 4;
for (int i=1; i<BLOCK_SIZE; i++){
    for(int j=1; j<BLOCK_SIZE; j++){
        System.out.print("+===");
    }
    System.out.println("+");
    for(int k=0; k<3; k++){
        for(int j=1; j<BLOCK_SIZE; j++){
            System.out.print("|   ");
        }
        System.out.println("|");
    }
}
for(int j=1; j<BLOCK_SIZE; j++){
        System.out.print("+===");
    }
System.out.println("+");

Another approach using some if statements

Here I make use of the fact that every (4n+1) line has '+' replacing '|' and '=' replacing 'whitespace'

int BLOCK_SIZE = 5;
int length = BLOCK_SIZE*4-4;
char one,two;

for(int i=0; i<=length; i++){
    if(i%4!=0){one='|';two=' ';}
    else{one='+';two='=';}
    for(int j=0; j<=length; j++){
        if(j%4==0) {
        System.out.print(one);
        }
        else {
        System.out.print(two);
        }
    }
    System.out.println(); 
}

Granted it's a homework problem, but we can have fun cracking them even if they serve no real life purpose. Such is the happiness that can be gotten from coding! :)

score 1 · Answer 3 · answered Feb 05 '12 at 04:57

Took sometime to achieve your expected result, see if it works for you?

public class Homework
{

    /**
     * @param args
     */
    public static void main(String[] args)
    {
            for (int line = 1; line <= 3; line ++)
            {

                NEWLINE:

                    for (int plus = 1; plus <= 3; plus++)
                    {
                        System.out.print("+");
                        if (plus == 3) 
                        {
                            for (int k = 1; k <= 3; k++)
                            {
                                if (line == 3)
                                {
                                    break NEWLINE;
                                }
                                System.out.println("");
                                System.out.print(" |         |          |");
                                if (k == 3)
                                {
                                    System.out.println();
                                    break NEWLINE;
                                }
                            }
                        }

                        for (int eq = 1; eq <= 6; eq++)
                        {
                            if (eq % 4 == 0)
                            {                           
                                break;
                            }
                            System.out.print("=");
                        }

                    }
            }
    }
}

In general it works, but how can I change constant height if I have this line: System.out.println("+===+===+");? — alya, Feb 05 '12 at 23:06
@alya that could probably be your homework as many posted their suggested here that give you many idea how to achieve your expected result in many ways. But probably Johnydep answer come the closest to your requirement. — Jasonw, Feb 06 '12 at 02:18

score 0 · Answer 4 · edited Aug 30 '16 at 19:12

This is simplest way.

public class Window {
    public static final int size = 3;

    public static void main(String[] args) {
        for (int x=0; x<2; x++) {
            for (int y = 0; y<2; y++){
                System.out.print("+");
                for (int z=0;z<size; z++) {
                    System.out.print("=");
                }
            }
            System.out.println("+");
            for (int i = 0; i<size; i ++) {
                for (int j = 0; j<2; j++) {
                    System.out.print("|");
                    for (int k = 0; k<size; k++) {
                        System.out.print(" ");
                    }
                }
                System.out.println("|");
            }
        }
         for (int y = 0; y<2; y++){
                System.out.print("+");
                for (int z=0;z<size; z++) {
                    System.out.print("=");
                }
            }
        System.out.println("+");
    }
}

Nick Rolando · Answer 5 · 2012-02-04T23:55:22.633

0

Here is one way

    int rows = 3;
    int cols = 4;
    String output1 = "";
    String output2 = "";
    for(int j = 0; j < cols; j++)
    {
        output1 += "|   ";
    }
    output1 += "|";
    for(int j = 0; j < cols; j++)
    {
        output2 += "+===";
    }
    output2 += "+";
    for(int i = 0; i < rows*4; i++)
    {
        System.out.println((i % 4 != 0)?output1:output2);
    }
    System.out.println(output2);

edited Feb 04 '12 at 23:55

answered Feb 04 '12 at 23:02

Nick Rolando

25,879
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I wrote it "I have to use nested for loops to print the repeated parts of the figure" – alya Feb 04 '12 at 23:16
You're going to need to use a conditional statement for this to distinguish between which type of row to display. I updated the code. Its better and uses only 1 `if` statement. – Nick Rolando Feb 04 '12 at 23:31
1

Really stupid homework: you can replace any if by a for (example, `if(i % 4 !=0)` is the same as `for(int cnt = 0; cnt < 1 && i % 4 != 0; cnt++)`... so just replace the ifs with this pattern ;) – s106mo Feb 04 '12 at 23:37
thanks, it looks good, but I need to use 4 for loops, it should be really easy, but I can't figure out it yet :( – alya Feb 05 '12 at 00:12

s106mo · Answer 6 · 2012-02-05T08:31:29.810

Could be refactored to be more pretty, but will work:

static String[][] array = { { "x", "="}, { "|", " "}};

public static void main(String[] args) {
    for(int y = 0; y < 9; y++) {
        for(int x = 0; x < 9; x++) {
            System.out.print(getSign(y, x));
        }
        System.out.print("\n");
    }
}

private static String getSign(int y, int x) {   
    int modY = y % 4;
    int modX = x % 4;
    return array[getPos(modY)][getPos(modX)];
}

private static int getPos(int mod) {
    return (mod & 1) | ((mod & 2) >> 1);
}

score -1 · Answer 7 · answered Feb 16 '15 at 04:21

public class Window{
    public static final int size=3;
    public static void main(String[] args){
       for (int p = 1; p <= 2; p++) {
            for (int i = 1; i <=2; i++) {
                System.out.print("+");
                for (int j = 1; j <= size; j++) {
                    System.out.print("=");
                }
            }
                System.out.print("+");
                System.out.println();
            for (int k = 1; k <= size; k++) {
                for (int i = 1; i <= 3; i++) {
                    System.out.print("|");
                    for (int j = 1; j <= size; j++) {
                        System.out.print(" ");
                    }
                }
                System.out.println();
            }
        }
        for (int i = 1; i <= 2; i++) {
            System.out.print("+");
            for (int j = 1; j <= size; j++) {
                System.out.print("=");
            }
        }
        System.out.print("+");
    }
}

What's this? Probably, you should explain why did you answer 3 y.o. question. Why do you think your answer is better than already posted answers? — default locale, Feb 16 '15 at 04:27

get the figure using nested for loops in Java

7 Answers7