A Loop program

grasshopper · **Posted:** Mon Mar 29, 2004 4:38 pm

i need help writing a program.. i`m just testing loops.. and i`m not sure how to print this but i just want to try.. anyone know the code?

I need to write a program which produces sets of triangles like these:
****
***
**
*
*
**
***
****

- ->I need to allow the user to deteremine how many sets of triangles will be produced.. I know I need this using TextIO...

I started programming this using a `for loop`. and then got stuck....

any suggestions? thanksss

Tony · **Posted:** Mon Mar 29, 2004 5:08 pm

well first you'll need a function to compile your line of astrics, similar to turing's repeat

code:

string repeat(int size)
{
String word = new String;
word = "";
for (int i=0;i<size;i++)
{
word = word + "*);
}
return word
}

now break your patten into decending and addending loops

code:

for (int i=size;i>=1;i--)
{
System.out.println(repeat(i));
}

for (int i2=1;i2<=size;i2++)
{
System.out.println(repeat(i2));
}

wtd · **Posted:** Mon Mar 29, 2004 6:03 pm

Good suggestion, tony, but instead of using String and + all over the place, use StringBuffer.

code:

String repeat(int size)
{
StringBuffer word = new StringBuffer("");
for (int i=0;i<size;i++)
{
word.append("*");
}
return word.toString();
}

It minimizes the number of temporary String objects created and increases memory efficiency.

grasshopper · **Posted:** Tue Mar 30, 2004 8:37 pm

umm.. i`m not worrying about adding the *`s for now because i don`t know where exactly to put that in my code.. i`ll try figuring that out later... but i have another question...

okay this program it`s suppose allow the user to determine how many sets... not how long the set is..

because in the following code...

code:

import java.io.*;

public class triangles
{
public static void main (String[] args)
{

int triangles;

System.out.print("Please determine how many sets of triangles you want to have produced: ");
triangles = TextIO.getlnInt();

for (int i=triangles;i>=1;i--)
{
System.out.println(i);
}

for (int i2=1;i2<=triangles;i2++)
{
System.out.println(i2);
}

} //end of main

} //end of class

the following gets printed out..

if user determines the number of sets to be 5 the following will print out..

5
4
3
2
1
1
2
3
4
5

if they chose 4..
4
3
2
1
1
2
3
4
and so on

but want i need it to print is..

if they chose five..
****
***
**
*
*
**
***
****

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

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

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

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

like print that whole set five times if they chose 5...

if anyone can help that would be great.. Very Happy

i hope it`s not a lot to ask for.. i`m a beginner at programming loops.. so there is still a lot i need to learn..but i`m sure will all these col programmers i`ll be fine.. wow this is starting to sound g.ay.. i`ll stop..
thanks

Tony · **Posted:** Tue Mar 30, 2004 10:29 pm

eh

code:

for (int i=0;i<triangles;i++)
{

for (int i1=4;i>=1;i--)
{
System.out.println(i1);
}

for (int i2=1;i2<=4;i2++)
{
System.out.println(i2);
}

}

grasshopper · **Posted:** Thu Apr 01, 2004 9:37 am

heey.. thanks for the help guys.. but i finally figured it out!!

code:

import java.io.*;

public class test
{
public static void main (String[] args)
{
//Variable Declaration

int triangles;
System.out.print("Please determine how many sets of triangles you want to have produced: "); //prompt for input
triangles = TextIO.getlnInt(); //read from keyboard

for (int count=1; count<=triangles; count=count+1)
{
for (int i=4;i>=1;i--)
{
for(int j= 1; j<=i; j=j+1)

System.out.print("*");
System.out.println ("");
} //first half of triangle

// begin second half of triangle
for (int i=1;i<=4;i++)
{
for(int j= 1; j<=i; j=j+1)

System.out.print("*");
System.out.println ("");

} //second half of triangle
System.out.print("\n");
}//end of first for statement

} //end of main
} //end of class

wtd · **Posted:** Thu Apr 01, 2004 3:54 pm

Now put all of the loops and such in a separate method. Putting everything in main is bad, bad bad! Smile

grasshopper · **Posted:** Fri Apr 02, 2004 1:16 am

lol is it?.. meh my teacher formatted it like that...

wtd · **Posted:** Fri Apr 02, 2004 3:09 pm

Yes. Teachers aren't always right. Wink

code:

class Exercise {
public static void printStuff() {
// code here
}

public static void main(String[] args) {
printStuff();
}
}

grasshopper · **Posted:** Sat Apr 03, 2004 2:08 pm

oo i c..
umm okay would you be able to help me with something else..as i`m still a beg. at programming..
i want to try this.. like see the code and see if it can help with something else i need to figure out..but not wanting the code for that..
hmm lets see...
alright.. how about a program that asks the user to enter 10 marks for a student.. umm then print out the student`s average, the maximum mark and the minumum mark..using a loop.. using only one variable to read all marks

can you help
Very Happy

Dan · **Posted:** Sat Apr 03, 2004 3:08 pm

well to start you will need 3 varibales.

an int for the max var

an int for the min var

an int for the sum of all the marks

now you will input the 1st mark and sotre it in all 3 vars (max, min, and sum)

next you will make a loop that runs for number of marks to be inputed -1 (becuse you all ready got the 1st mark).

then in the loop you input the number in a temp var. add it to sum and check to see if it is bigger then max or smaller then min. if it is you will set it as the one it is biger or smaller then.

then end the loop and output the max, the min and the sum div the num of marks to get the avg.

wtd · **Posted:** Sat Apr 03, 2004 7:54 pm

You'd want something like the following untested program.

code:

import java.lang.*;
import java.io.*;

class Exercise {
public static BufferedReader keyboard =
new BufferedReader(new InputStreamReader(
System.in));

private class StudentGradeset {
private double grades[10];
private int gradesInput;

public StudentGradeSet(double initialGrade = 0.0) {
grades = new double[10];
gradesInput = 0;
int len = grades.length;
for (int i = 0; i < len; i++)
grades[i] = initialGrade;
}

public double sumOfGrades() {
double total = 0.0;
int len = grades.length;
for (int i = 0; i < len; i++)
total += grades[i];
return total;
}

public double minGrade() {
double min = 0;
int len = grades.length;
for (int i = 0; i < len; i++)
if (grades[i] < min)
min = grades[i];
return min;
}

public double maxGrade() {
double max = 0;
int len = grades.length;
for (int i = 0; i < len; i++)
if (grades[i] > max)
max = grades[i];
return max;
}

public double averageGrade() {
return sumOfGrades() / grades.length;
}

private void inputGrade(BufferedReader input) {
grades[gradesInput++] = Double.parseDouble(input.readLine());
}

public void inputGrades(PrintStream output, BufferedReader input) {
while (gradesInput < grades.length) {
output.print("Please input a grade: ");
inputGrade(input);
}
}

public void outputResults(PrintStream output) {
output.println("Max grade: " + maxGrade());
output.println("Min grade: " + minGrade());
output.println("Avg Grade: " + averageGrade());
}

public static void main(String[] args) {
StudentGradeSet grades = new StudentGradeSet();
grades.inputGrades(System.out, keyboard);
grades.outputResults(System.out);
}
}

And just in case seeing the problem solved in other languages can be of help, I've attached some other samples.

grasshopper · **Posted:** Sun Apr 04, 2004 3:47 pm

uuuhhh.. what?
i don`t think it was suppose to get that confusing..

Sad

grasshopper · **Posted:** Sun Apr 04, 2004 9:14 pm

okaay umm how about i forget that program.. i confused myself..
how about..
A program that asks the user to enter a mark. The program then prints out one line. The word and the mark will be separated by enough dots so that the total line length is 30:
Enter your name: Super
Enter your mark: 95
Super's mark is"¦"¦"¦..95

- ->to print the dots, use System.out.print(".") inside a loop body
- ->might need the following code

code:

String inputString;
Int times;

....

Times= inputstring.length() //times will hold the number of characters in inputString

i don`t know how i`d program that and if i`d use a while or for loop

this is my strcutre so far. (without the public static void main...etc.. etc..)

code:

//Variable Declaration

String usersName; //the user's name
String inputString;
int times; //will hold the number of characters in inputString
int mark;

//Variable Initialization and Input

System.out.print("Please enter your name: "); //prompt for input
usersName = TextIO.getln(); //read from keyboard

System.out.println("Please enter a mark: ");
mark = TextIO.getlnInt();

//Program Processing and Output
// the process and output i don`t get

help?

Dan · **Posted:** Mon Apr 05, 2004 4:28 pm

TextIO eh? i dont think that is a standered I/O method, u using the Robot java text book by any chance?

any way that dose not matter. This is what i think u need:

code:

int length = usersName.length() + 11;

if(mark >= 10)
{
length = usersName.length() + 12;
}
else if(mark == 100)
{
length = usersName.length() + 13;
}

System.out.print(usersName + "'s mark is");

for (int i = 0; i < 30-length; i++)
{
System.out.print(".");
}

System.out.print(mark + "\n");

in this part:

code:

int length = usersName.length() + 11;

if(mark >= 10)
{
length = usersName.length() + 12;
}
else if(mark == 100)
{
length = usersName.length() + 13;
}

length is a var to rep how many chars are in the line minus the "."s. u have to add in 10 for the "'s mark is" part and 1, 2 or 3 for the length of the mark.

the for loop part runs for 30 - the length of the line with out "."s and thous will put in the right number of "."s. some error checking should probly be added to this in case there is - dots or 0 dots needed.

by the way what corse u talking and where? that TextIO is alot like one of the methods in a book i was using for my course.

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