3.times {print 'x '}
1.upto(5) {|i| print i, " "}
99.downto(95) {|i| print i, " "}
50.step(80,5) {|i| print i, " "}

Integer also support several useful iterators. Class Numeric also provides the more general method step, which is more like a traditional for loop　即为：整型也支持迭代

结果如下：x x x 1 2 3 4 5 99 98 97 96 95 50 55 60 65 70 75 80

注意：求一个数的绝对值，在ruby和C中有不同方法：

　　　ruby: num.abs

             C:abs(num)

评论