ref: 169cceaef46664b809cc13f52f9cfaa88275d610
dir: /Loops/README.md/
# Loops Looping in Limbo is similar to looping in C. Supported loop formats are for, while, and do-while. ## Source ### loops.b:18,23 for(i := 0; i < 10; i++){ if(i % 2 == 0) continue; print("%d\n", i * i); } A for loop consists of an initialization, qualification, operation, and post-iteration sequence. Before the loop begins, but before the initial check, `i := 0` is run. After each loop iteration, `i++` is performed, then `i < 10` is checked. The `continue` keyword, from the point it is called, skips to the next loop iteration. In this case, `continue` is called if `i` is an even number. If `i` is an odd number, `i²` is printed. Note that the `continue` keyword does not skip the post-iteration operation. ### loops.b:28,29 while(n) print("%d\n", n--); A while loop will check the qualifier for whether to enter another iteration, then, perform its operation. This loop will print the value of `n` in the range [7,1]. Note that in this case the braces are omitted. ### loops.b:33,36 do{ print("%d\n", ++n); break; }while(1); A do-while loop will perform its operation, then check the qualifier for whether to enter another iteration. In this case, the qualifier is a constant which is quantified as a true value, so, this loop would iterate forever. The `break` keyword interrupts iterative processing. In this case, it terminates the loop immediately after the print on its first iteration. Note that we reuse the value of `n`, In this case, the incremented value of `n` is printed, as when the preceding loop ends, the value of `n` is 0. ## Demo ; limbo loops.b ; loops == for 1 9 25 49 81 == while 7 6 5 4 3 2 1 == do 1 ; ## Exercises - Try reversing the ++/-- operators in different places, what happens? - Try omitting various portions of the for loop syntax, what happens? - Is `for(;;);` an infinite loop? - Make the condition for a loop something similar to --n, how many iterations does it run for?