break / continue

Summary#

break leaves the enclosing loop. continue abandons this pass and goes to the next one. Both behave exactly as in C# — including the part that catches people out: inside a switch, break leaves the switch, not the loop around it.

Signature#

break;      // stop looping
continue;   // skip the rest of this pass

Description#

continue — skip this one#

entity Order {
  [Required] string Code;
  decimal Total;
  bool Cancelled;
}

decimal LiveTotal() {
  var total = 0m;
  foreach (var o in Order.Where(x => x.Total > 0).ToList()) {
    if (o.Cancelled) { continue; }    // not this one — next
    total += o.Total;
  }
  return total;
}

break — stop entirely#

string FirstBig(decimal threshold) {
  var found = "";
  foreach (var o in Order.Where(x => x.Total > 0).ToList()) {
    if (o.Total >= threshold) {
      found = o.Code;
      break;                          // done — no point looking further
    }
  }
  return found;
}

Why didn't break leave my loop? — the switch trap#

This is the one to remember. Inside a switch that sits in a loop, break ends the switch, and execution continues after it — inside the same pass of the loop. It does not leave the loop.

continue, by contrast, passes straight through the switch and continues the loop:

int SumNonZero(int[] xs) {
  var total = 0;
  for (int i = 0; i < xs.Length; i++) {
    switch (xs[i]) {
      case 0: continue;               // skips to the next i — the loop's next pass
      default: break;                 // leaves the SWITCH; falls through to the += below
    }
    total += xs[i];
  }
  return total;
}

If you want to leave the loop from inside a switch, you need a flag, or to restructure the loop — exactly as in C#. This is not a wart we introduced; it is C#'s rule, and we kept it rather than invent a different one you would have to learn twice.

See also#

• foreach · while · for — the loops these act on
• switch — where break means something different