loop and a half controlled [closed]

Question

When do we use loop and a half? Also, should someone briefly elaborate how to write its code?

Answer 1

You use loop-and-a-half to avoid repeating code from outside the loop to the inside. Example:

read a;
while a != b do
  stuff;
  read a;
end

becomes

while true do
  read a
  if a == b then break
  stuff;
end

Now I only have the read in one place.

Answer 2

As an aside, I'd like to add that the scope of the variable (assuming a is a local variable in this idiom) is minimized as compared to the alternative case, where a is still in scope even after the while loop terminates. Minimizing the scope of local variables is considered good practice whenever possible (Josh Bloch, Effective Java, Item 45).