In the do-while c++ loop format, do you have to put an increment/decrement operator like you do for the while loop?

Question

The syntax format for the while loop, in c++, is usually:

while (expression)
{
statements;
increment or decrement operator;
}

For a do-while loop, does the syntax format also carry an increment/decrement operator?

Answer 1

you do not need either a decrement or increment operator. Just some condition that changes so your loop will end.

Even that is not necessary. i sometimes use a while(true){} loop. You can exit the loop with a break or return statement.

Answer 2

You pretty much need *something* to change about the condition so you can exit the loop. If the condition never changes, then the loop will never end. But that doesn't mean you need to increment/decrement. You might get user input and loop while the input is not "Quit". You might have a loop that runs until it hits the end of a file, or the end of a database query.



I would say that if you're just incrementing or decrementing every time you loop, you would be better off with a for loop instead of a while or do-while loop.

Answer 3

It depends for what purpose you are using do-while() loop

- If you are using do-while() for input validation e.g. Enter a number from 1-9

then there is no need for Increment/Decrement operator



- If you are using do-while() for couting or finding even or odd number

then you have to use Increment/Decrement operator

Answer 4

Yes. You do have to have a value that changes that is used to determine whether or not the loop repeats. If there was no increment/decrement operator then the loop would continue forever.

Answer 5

roger's answer is good, just adding that the only difference between while and do-while is that the latter always runs at least once, while a while loop can get skipped entirely if the condition starts out evaluating to false.

Answer 6

No. Please read the excellent answers you got from Roger and Chris. Then go out and find whomsoever lied to you and slap that person up side the head repeatedly with a sea bass!