Prime Directive
Write a Ruby program whose output is exactly this:
2 3 5 7 11 13 17 19 23 29
31 37 41 43 47 53 59 61 67 71
73 79 83 89 97 101 103 107 109 113
127 131 137 139 149 151 157 163 167 173
179 181 191 193 197 199 211 223 227 229
233 239 241 251 257 263 269 271 277 281
283 293 307 311 313 317 331 337 347 349
353 359 367 373 379 383 389 397 401 409
419 421 431 433 439 443 449 457 461 463
467 479 487 491 499 503 509 521 523 541
547 557 563 569 571 577 587 593 599 601
607 613 617 619 631 641 643 647 653 659
661 673 677 683 691 701 709 719 727 733
739 743 751 757 761 769 773 787 797 809
811 821 823 827 829 839 853 857 859 863
877 881 883 887 907 911 919 929 937 941
947 953 967 971 977 983 991 997
Of course, I'm not going to give you credit for just writing a
print statement. You have to compute the values, and
print then one lines of 10 values as shown.
The values, if you've not figured it out, are the prime
numbers below 1000. You are to compute them using the
Sieve of
Eratosthenes (either the classic version or
one of the fancier versions documented in the links).
There are
many ways to code this, but you should take advantage of
the Ruby language. Some things you could do,
particularly using
array methods:
- Use the each method to scan through arrays.
- Use the join method method of an
array to print an array, or a slice
of an array, with spaces between.
- Make a range and use the each method to go through the range.
- Use the delete_if or compact methods to get rid of
unwanted array members (perhaps evil multiples).
- If you have an array of primes to print, you could perhaps loop on a
slice method call to generate the lines.
Bonus up to 5 points for how much a working solution does
not look like a translated Java program.
When your program works, is nicely formatted and documents,
submit it using
this form.