excercise

the book says: write a program that displays the following patterns seperately, one below the other. use for loops to generate the patterns. All stars should be printed by a single statement of the form Console.Write('*'); A statement of the form Console.WriteLine(); can be used to position the next line. A statement of the form Console.Write(' '); can be used to display spaces for the last two patterns. there should be no other output statements in the program.

Code:

---

*
**
***
****
*****
******
*******
********
*********
**********
**********
*********
********
*******
******
*****
****
***
**
*
**********
 *********
  ********
  *******
    ******
    *****
      ****
      ***
        **
        *
        *
        **
      ***
      ****
    *****
    ******
  *******
  ********
 *********
**********

---

the code is

Code:

---

using System;

namespace ex5_7
{
       
        class Class1
        {


                [STAThread]
                static void Main(string[] args)
                {
                        //first right triangle of stars bottom left
                        for(int outer=1; outer<=10; outer++)
                        {
                                for(int inner=1; inner<=outer; inner++)
                                {
                                        Console.Write('*');
                                }
                                Console.WriteLine();
                        }
                        //second right triangle top left
                        for(int outer=10; outer>0; outer--)
                        {
                                for(int inner=1; outer>=inner; inner++)
                                {
                                        Console.Write('*');
                                }
                                Console.WriteLine();
                        }
                       
                       
                        //third right triangle top right
                        int noofstars = 10;

                        for(int outer=1; outer<=10; outer++, noofstars--)
                        {               
                                for(int stars=noofstars; stars>0; stars--)
                                {
                                        Console.Write("*");
                                }
                                Console.WriteLine();
                                if(outer==10)
                                        break;
                               
                                for(int space=1; space<=outer; space++)
                                        Console.Write(" ");
                        }

                        //fourth right triange bottom right
                        noofstars=1;

                        for(int outer=10; outer>0; outer--, noofstars++)
                        {               
                                for(int space=1; space<outer; space++)
                                        Console.Write(" ");
                               
                                for(int stars=1; noofstars>=stars; stars++)
                                {
                                        Console.Write("*");
                                }
                                Console.WriteLine();
                        }

                       
                }
        }
}

---

the next excercise asks...modify excercise 5.7 to combine your code from the four seperate triangles of asterisks into a single program that prints all four patterns side by side, making clever use of nested for loops.

i have started by writing down what i need to do in pseudo code which is bacically a sequential list of actions but i have no idea how to 'get off the ground' on this one, i would appreciate some feedback please. the problem is the the cursor gets drawn linearly and nested for loops work like car mileometers, i cant think how to make both work together...pls help


luigi

30 views and still nothing, guess im on my own

this is the code i came up with, however, i dont think this is what Deitel are looking for, is this 'clever' use of nested loops?

Code:

---

using System;

namespace Ex5_8
{
       
        class Class1
        {
                [STAThread]
                static void Main(string[] args)
                {
                        int midspaces = 0, countd = 10, countu = 1;
                       

                        for(int outer=0; outer<10; outer++, countd--, countu++)
                        {
                                for(int h=0; h<=outer; h++)//1st stars triangle needs to inc on each loop from 1 to 10
                                        Console.Write('*');

                                for(int i=1; i<=countd; i++)
                                        Console.Write(' ');//1st space triangle needs to dec from 9 to 0
                                       
                                for(int j=1; j<=countd; j++)
                                        Console.Write('*');//2nd star triangle needs to dec from 10 to 1
                                       
                                for(int k=0; k<midspaces; k++)
                                        Console.Write(' ');//middle space triangle needs to inc from 0 to 18
                                        midspaces = midspaces+2;//in steps of 2

                                for(int l=1; l<=countd; l++)//3rd star triangle needs to dec from 10 to 1
                                        Console.Write('*');
                                       
                                for(int m=1; m<=countd; m++)//4th space triangle needs to dec from 9 to 0
                                        Console.Write(' ');

                                for(int n=0; n<countu; n++)//4th star triangle needs to inc from 1 to 10
                                        Console.Write('*');

                                Console.WriteLine();//newline
                        }
                       
                }
        }
}

---

which produces the following output

Code:

---

*          ********************          *
**        *********  *********        **
***        ********    ********        ***
****      *******      *******      ****
*****      ******        ******      *****
******    *****          *****    ******
*******    ****            ****    *******
********  ***              ***  ********
*********  **                **  *********
********** *                  * **********

---

i would really appreciate some feedback, there must be someone reading this forum who has worked with for nested for loops

thanks in advance

I don't know C#, but I was just wondering what the [STAThread] does? Does it indicate which class has Main?

Quote:

---

is this 'clever' use of nested loops?

---

You could definitely do it in a "cleverer" way. In C (sorry, as mentioned, I don't know C#):

Code:

---

#include <stdio.h>

int main(void) {
    int x, y, z;

    for(x = 0; x < 10; x ++) {
        for(z = 0; z < 4; z ++) {
            for(y = 0; y < 10; y ++) {
                if(!z || z == 3) putchar(y <= x ? '*' : ' ');
                else putchar(y <= (10-x) ? '*' : ' ');
            }
        }
        printf("\n");
    }
}

---

Something like that. I don't have a compiler on this computer, so I can't tell you if it works.

dwks
i think i read the [STAThread] is something to do with the dot net environment about threading, you can take it out and it doesnt seem to make any difference. thanks for your algorithm, the language doesnt matter, its the idea that helps

:)
luigi

hi dwks

cant make sense of the if statement, it wint complie for me. had to make it if(z == 3)

as z is an integer how can you have NOT z?

i will play with the code anyway, anyone else willing to help please do

luigi :)

Blog about [STAThread]: http://blogs.msdn.com/jfoscoding/arc...07/406341.aspx

Simplified meaning: http://www.publicjoe.f9.co.uk/vbnet/vb03f.html

In C,

Code:

---

if(!z || z == 3)

---

is the same as

Code:

---

if(z == 0 || z == 3)

---

In C/C++, anything that is non-zero is true. So you can use

Code:

---

if(z)

---

and the if will execute if z is anything but zero. This code

Code:

---

if(!z)

---

does the opposite, executing the if if z is zero.

Is C# like Java? (if(z) is invalid in Java . . . .)

this is what i came up with...

Code:

---


using System;

namespace Ex5_8
{
       
        class Class1
        {
                [STAThread]
                static void Main(string[] args)
                {


                        int a, b, c;

                        for(a = 1; a <= 10; a++)
                        {
                                for(b = 1; b <= 4; b ++)
                                {
                                        for(c = 1; c <= 10; c++)
                                        {
                                        if(b==1)Console.Write(c <= a ? '*' : ' ');
                                        else if(b==2)Console.Write(c <= (11-a) ? '*' : ' ');
                                        else if(b==3)Console.Write(c >= a ? '*' : ' ');
                                        else if(b==4)Console.Write(c <= (10-a) ? ' ' : '*');
                                        }
                                }
                                Console.WriteLine();
                        }

                       
//output                       
//*        ********************        *
//**        *********  *********        **
//***      ********    ********      ***
//****      *******      *******      ****
//*****    ******        ******    *****
//******    *****          *****    ******
//*******  ****            ****  *******
//********  ***              ***  ********
//********* **                ** *********
//***********                  ***********



                       
                }
        }
}

---

thank you for your feedback dwks
any feedback on improvements would be welcomed

luigi