First steps in ruby. Printing a triangle of stars
I’m going to try and write some simple ruby programs. Here’s the first one. It prints a triangle of stars like this:
1 2 3 4 5 6 7 8 9 10 11 | ****************************************************************** |
And here is the code:
1 2 3 4 5 6 | star_string = "*"10.times do puts star_string star_string = star_string + "*"end |
I hope you can understand it. The program creates a string called “star_string”. Then it loops 10 times. Each time it loops it prints (puts) out star_string, and adds another * to the string. That way star_string gets longer and longer.
I’m also going to show you how this is done in C++. If you don’t want to learn C++ you don’t need to look at this. But C like languages are so common it’s worth at least gaining some familiarity with the syntax.
#include
#include
using namespace std;
int main() {
string star_string = “*”;
for(int n=0;n<10;n++) { cout << star_string << endl; star_string = star_string + "*"; } } [/sourcecode] Can you modify the program so it prints more than one triangle, like this? [sourcecode language="html"] * ** *** **** ***** ****** ******* ******** ********* ********** * ** *** **** ***** ****** ******* ******** ********* ********** [/sourcecode] Post your solution in the comments sections below. Everytime someone posts a solution, I'll try to post a new example and problem the next day. The part 2 is now HERE.
RSS
btw, there are some notes on using Ruby on Mac OS X and other platforms here.
Or for a more rubyish way:
10.times do |n|
puts "*" * n
end
I’m not sure what “rubyish” means in this case. I’ve just started learning Ruby. Is “* n” a universal concept in Ruby? (i.e. repeat the previous statement n times) or does it only apply to puts? I take it |n| means put the current number of iterations in n?
Thank you for your post! I tried it.
2.times do
star_string = “*”
10.times do
puts star_string
star_string = star_string + “*”
end
end
P.S. It’s not a star☆
[…] First steps in ruby 2: Variables and chop 01. October 2011 · Write a comment · Categories: Uncategorized This builds on the pervious article here. […]
here is an empty triangle code
*
**
* *
* *
* *
* *
* *
* *
* *
**********
while (count 2 && count < user_num)
if(count == user_num)
break
end
puts"*" + " " * (count – 2) + "*"
count+=1
end
end
Here’s a simple way to print a perfect pyramid with ruby:
while i <=50
if i.odd?
puts(print ("*"*i).center(100))
end
i +=1
end