Question

hey I’m looking for are clean solution to this problem:

i start the loop with i = 0 in the second loop step the i = 1, then i = -1 and then i = 2 ect.

how to programm this with a for loop in a clean way?

Answer 1

If you don’t mind having the inner loop appear 3 times:

f(0);
for (var i = 1; i <= 3; ++ i) {
  f(i);
  f(-i);
}

2 times with an if:

for (var i = 0; i <= 3; ++ i) {
  f(i);
  if (i > 0)
     f(-i);
}

single time but with an ugly expression:

for (var j = 1; j <= 7; ++ j) {
   var i = j / 2;
   if (j % 2) i = -i;

   f(i);
}