Is there a one-line function that generates a triangle wave?

In a similar way that modulo generates a sawtooth wave. It doesn't have to be continuous. here is what i mean: ``` int m = 10; int x = 0; int i = 0; while (i < m*3) { printf("%d ", x); x++; x = x % m; i++; } ``` generates a sequence 0..9, three times which looks like this: note that the slope on the right side of the peak is just a graphing artifact The one-liner in this case is x = i++ % m What I want is this: If you know one-liners for the other wave forms (sine, square), that would be good to know as well. Update: everyone's answers have been very helpful and I have a follow-up question. What would be added to the triangle wave function to make the slope of the lines curve in or out like this: Thanks everyone, your varied answers helped me see the problem from a larger perspective. Special thanks to Noldorin for his take on extending the equation to quadratic curves.