Difference between "while" loop and "do while" loop

user_417552 0
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What is the difference between while loop and do while loop. I used to think both are completely same.Then I came across following piece of code:

do {
        printf("Word length... ");
        scanf("%d", &wdlen);
    } while(wdlen<2);

This code works perfectly. It prints word length and tascans the input. But when I changed it to

while(wdlen<2){
        printf("Word length... ");
        scanf("%d", &wdlen);
    }

It gives a blank screen. It do not work. So there is some functional difference between both loops. Can anybody explain it?

Is there any other difference in these two?

c loops
16 Answers

The difference between a while constructs from Step 1 versus a do while is that any expressions within the do {} will be running at least once regardless of the condition within the while() clause.

println("\nStep 2: How to use do while loop in Scala")
var numberOfDonutsBaked = 0
do {
  numberOfDonutsBaked += 1
  println(s"Number of donuts baked = $numberOfDonutsBaked")
} while (numberOfDonutsBaked < 5)

Here is detail explaination: Explanation Visit: coderforevers

user_61412450

The most important difference between while and do-while loop is that in do-while, the block of code is executed at least once, even though the condition given is false.

To put it in a different way :

  • While- your condition is at the begin of the loop block, and makes possible to never enter the loop.
  • In While loop, the condition is first tested and then the block of code is executed if the test result is true.
user_40458230
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