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Java Forum / General / March 2006Is there a better way of getting the following output: ?
I've written the following code: public class Sand { public static void main( String args[] ) { System.out.println( "*****" ); System.out.println( " *** " ); System.out.println( " * " ); System.out.println( " *** " ); System.out.println( "*****" ); } } What i want to know is.. Is there a better (quicker/more efficient) way of obtaining the same output? ***** *** * *** ***** Thanks.. When is your homework due? Next week.. And i've done it.. As you can see. I only want to know if there are other ways of doing it.. >What i want to know is.. Is there a better (quicker/more efficient) way >of obtaining the same output? [quoted text clipped - 4 lines] > *** >***** consider these numbers 0 5 0 1 3 1 2 1 2 1 3 1 0 5 0 If you could generate them in a loop you could generate that pattern ad infinitum. The code would not be as terse or as comphensible as what you have.  SignatureCanadian Mind Products, Roedy Green. http://mindprod.com Java custom programming, consulting and coaching. hhm.. I don't think I've done loops yet.. And the book I'm following (Deitel's Java how to Program) asks at the end of the chapter to do something similar, but doesn't provide any examples of the source code.. i guess spaces will have to do.. Incidentally, out of my own personal interest, would it be too complicated to create such loop, if my knowledge extends to creating simple algorythms? > Incidentally, out of my own personal interest, would it be too > complicated to create such loop, if my knowledge extends to creating > simple algorythms? It's conceptually simple, but you might find it a bit tricky in practise. For one thing you need to be comfortable with loops (and nested loops), and I gather you haven't reached that stage yet. For the other, it's a bit fiddly getting the exact numbers right, how many blanks do you need to print on line n, and so on. Some programmers find that kind of thing easy, but others find it fustrating and difficult to get exactly right[*]. ([*] I'm in the latter camp. I just tried programming it myself and it took me a few attempts to get it working correctly -- which is exactly what I expected). -- chris > I've written the following code: > [quoted text clipped - 12 lines] > What i want to know is.. Is there a better (quicker/more efficient) way > of obtaining the same output? Not quicker/more efficient, but different...: public class Sand { static final String hourGlass = "*****\n" + " *** \n" + " * \n" + " *** \n" + "*****\n"; public static void main( String args[] ) { System.out.println( hourGlass ); } } SignatureDag. > I've written the following code: > [quoted text clipped - 12 lines] > What i want to know is.. Is there a better (quicker/more efficient) way > of obtaining the same output? When you say "quicker/more efficient", do you mean for the JVM, or for the programmer? I.e. do you mean "It takes less time for the computer to run this program", or do you mean "I, as a programmer, have to spend less time writing down this program"? - Oliver >> I've written the following code: >> [quoted text clipped - 12 lines] >> What i want to know is.. Is there a better (quicker/more efficient) way >> of obtaining the same output? public class Sand { public static void main( String args[] ) { System.out.println( "*****\n *** \n * \n *** \n*****" ); } } > When you say "quicker/more efficient", do you mean for the JVM, or > for the programmer? I.e. do you mean "It takes less time for the > computer to run this program", or do you mean "I, as a programmer, have > to spend less time writing down this program"? > > - Oliver SignatureJosé Urzúa Reinoso http://jose.cl uum.. the having to spend less time writing the program one.. Though I don't mind spending more time writing the program, it just seems like there might be a better way of writing this particular one without using such elementary processes.. hhm.. okay.. i just read the question again and i do have to use loops.. or nested loops.. > hhm.. okay.. i just read the question again and i do have to use > loops.. or nested loops.. Well, if you have to use nested loops, then your original program won't solve the problem. So you better give it another stab before we start posting solutions for you. - Oliver Yep.. Will post my solutions when I do it.. Thanks to all.. hhm.. Okay.. This is what I have so far.. import java.io.*; import java.math.*; public class Pattern { public static void main( String args[] ) throws IOException { int y=1; int x=1; int z=1; int gap = 4; int size=9; for (x=1; x<=size; x+=2) { for (z=1; z<=gap; z++) { System.out.print(" "); } for (y=1; (y<=(x)); y++) System.out.print("*"); System.out.println(); gap--; } } } i've made it this far and it seems as if though I can't get my head around getting the top half to work.. > hhm.. > Okay.. This is what I have so far.. [quoted text clipped - 29 lines] > i've made it this far and it seems as if though I can't get my head > around getting the top half to work.. You've got the right idea. This program only prints the "bottom" triangle. Consider this strategy: Put this program aside for now, and start writing a new program; one which only prints the "top" triangle. Then, take both programs and try to combine them together, to see if you can produce the whole figure. You'll probably have 2 sets of nested loops, e.g. for (something) { for (something) { do something; } } for (something) { for (something) { do something; } } - Oliver Hi Ivan: Well as you can probably tell you've solved it the quicker more efficient way but probably not the better way (depending upon one's definition of better.) You can imagine how it would be to write an 80-row version or if having completed it the "boss" says "oh but the user gets to choose the characters to use did I forget to tell you that?" I can post the code but you should try it first. Don't think of this as asterisks and spaces it's all about a pattern and that requires an algorithm. Roedy pointed out the pattern you should be trying to solve. Notice one thing however that the right digit is always the same as the left digit. That means you only need to solve for the number of stars and 1/2 the number of spaces. I wrote it so a maximum number of rows plus two characters can be set and it generates the pattern. The only restriction is that the maximum rows must be odd which is the only way you can get one star in the middle. I did use nested loops but they don't look nested since I put the second loop into it's own procedure so I didn't have to repeat it 3 times. I noticed your code earlier and your comment about getting the "top-half" to work. Avoid thinking about it as having two parts. I recommend an iterative process so make sure you can print <n> rows of <n> stars. Then make it print the same <n> rows but printing <n1> spaces (I think you should use periods though, you can see them better) plus <n2> stars plus <n1> spaces. So you would get something like this: ...*****... ...*****... ...*****... ...*****... ...*****... It will be working but clearly it's just a square. So now the algorithm comes down to "how do increase the number of periods and reduce the number of stars (until there is one star) and then reverse the process"? Tom >> hhm.. >> Okay.. This is what I have so far.. [quoted text clipped - 50 lines] > > - Oliver hi.. I think I'm almost there.. It's getting rather frustrating and it feels like I hit another brick wall.. public class Star { public static void main( String args[] ) { int size = 9; int insize = size; // Start inverted triangle for( int i = 0 ; i<=size ; i++ ) { for( int k = 0 ; k<=i ; k++ ) { System.out.print(".") ;// first print space equal to i } for ( int j=0 ; j <= insize ; j++ ) { System.out.print("* ") ;// print star space } insize = insize -1 ; System.out.println(); } // end inverted triangle // start upright triangle int line = 1 ; for( int i = size ; i >= 1 ; i-- ) { for( int k = 1 ; k <= i ; k++ ) { System.out.print(".") ; } for( int j = 0 ; j <= line ; j++ ) { System.out.print("* "); } line++ ; System.out.println() ; } // end upright triangle } } the pattern I'm getting is as follows 10 9 8 7 6 5 4 3 2 1 2 3 4 5 6 7 8 9 10 I'm looking for 9 7 5 3 1 3 5 7 9 I hope there's SOMETHING i can do to my code.. And not have to start again.. > the pattern I'm getting is as follows > [quoted text clipped - 5 lines] > I hope there's SOMETHING i can do to my code.. And not have to start > again.. Try moving your indexes by twos instead of ones? (for example, use "k+=2" instead of "++k") > hi.. > [quoted text clipped - 57 lines] > I hope there's SOMETHING i can do to my code.. And not have to start > again.. You're printing a star, then a space ("* "), my understanding is that this is NOT what you want, but given the comments present in the source code, it looks like you were doing this intentionally. Anyway, you are almost done. If you change a single character, it will work. - Oliver >for( int k = 1 ; k <= i ; k++ ) > { [quoted text clipped - 4 lines] > System.out.print("* "); > } another sort of trick you can use for this sort of problem looks like this for( int i = 1 ; i <= n ; i++ ) { System.out.print( ( boolean expression of i ) ? '*' : ' ' ); } I leave it to you to figure out what the expression looks like. hint mathmaticians like to write things like this if ( a _<_b _<_ c ) which in Java comes out if ( a <= b && b <= c ) SignatureCanadian Mind Products, Roedy Green. http://mindprod.com Java custom programming, consulting and coaching. Hi Ivan: You are getting closer. I think you've recognized a sequence but I don't think you're seeing the pattern. It's a formula where the star length decreases by two at each step until there is one star at which point the star length increases by two. At the same time the blank length adjusts by the same value in the opposite direction. Interestingly you don't have to keep track of the number of blanks only the stars because you can calculate blanks at any time by subtracting stars from total rows. I originally wrote my version as two procedures in a dummy class but I've subsequently rewrote it as a static class which can be used as follows: Stars.ProcessX( "*", ".", 5 ); Stars.ProcessX( "X", ".", 8 ); It even self-corrects in the second example. I check to see if the number of rows is odd and if it isn't I add one to it. One other idea (I know you're learning this) but you want to encapsulate whatever you can to offer reuse. You are making a lot of calls to System.out.print() for instance. It doesn't matter how many call you make but that they are scattered throughout the code and that make it difficult to change if the next thing you want to do is draw graphics instead. I put all mine in a private method named StarsOut(). It is using System.out.print() but the mechanism for all output is there and there alone. Seemingly I could add other processes to my Stars class that could output other shapes as well. You would end up having to rewrite Main(). One step at a time though :-) > hi.. > > I think I'm almost there.. > > It's getting rather frustrating and it feels like I hit another brick > wall.. <code snipped> > the pattern I'm getting is as follows > [quoted text clipped - 5 lines] > I hope there's SOMETHING i can do to my code.. And not have to start > again.. Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
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