努力将for循环转换为do..while循环

Question

I'm struggling to convert a for loop into a do..while loop, seems like an unnecessary exercise to me but maybe it'll be useful to me later on. I can't get my head round how I'd re-design it, I can pretty easily put it into a while loop but not a do..while.

The for loop is below;

    int d;
    int n = 55;

    for (d = 0; n != 0; d++)
    {
        n /= 10;
    }
    System.out.println(d);

Any help is appreciated :)

Answer 1

I think this will do:

    int d = 1;
    while ((n /= 10) != 0) {
        d++;
    }

Answer 2

Here's a solution without do .. while / while but a simple infinite loop (which has the greatest flexibility):

int d = 0;
int n = 55;
// loop
while (true) {
    n /= 10;
    d++;
    //break condition
    if (n == 0) {
        break;
    }
}
System.out.println(d);

Answer 3

int d;
int n = 55;

d = 0;
do {
    n /= 10;
    d++;
} while(n != 0)

System.out.println(d);

this way the d variable, which just count how many times the loop is executed, will be updated the same way as the for loop would do.

Note that this will work only if n is not 0 at the beginning of the loop. In other words, if n is set to 0 in the second line of code the result will be different from the for loop, because the do..while loop always gets executed at least once, therefore the output would be 0 in the "for loop" case and 1 in the "do..while loop" case.

Answer 4

You could implement it with a do...while loop like

int d = 0;
int n = 55;

do {
    n /= 10;
    d++;
} while (n != 0);
System.out.println(d);

But I would suggest you use Integer.toString(int) and take the length of the resulting String instead like,

System.out.println(Integer.toString(n).length());

Answer 5

try this:

 int d=0;
 int n = 55;
 do{ 
  n /= 10;
  d++;
 }while(n != 0);
 System.out.println(d);

all loops are the same, basically they need a condition . in your case your condition is (n!=0) . for loop is good because its 'tidier'.