For 循环 - Java

Question

I'm sure this is super simple, but I keep getting nothing. The instructions say:

"Write code that prints: firstNumber...2 1 Print a newline after each number. Ex: firstNumber = 3 outputs

3
2
1

Here's: the code:

public class ForLoops {
   public static void main (String [] args) {
      int firstNumber;
      int i;

      firstNumber = 3;

      for (i = 3; i <= 1; --i) {
         System.out.println(i);
     }
   }
}

My thought process is since it wants me to count down from 3 to 1, I make i equal to 3, then it will count down for everything until i equals or is less than 1 with the --i.

If that makes sense.

Answer 1

The problem is in the loop condition, that will never be True , Change the condition to this:

i >= 1

Because in this condition:

i <= 1

The current value of i is 3, and 3 is not smaller than ( < ) or equal to ( = ) 1 , so the condition will be False at the first place, and code inside for loop will never gets executed.

Also, you've created a variable firstNumber , which I believe is the starting point of counter variable so you can change this line:

for (i = 3; i <= 1; --i)

to this:

for (i = firstNumber; i >= 1; --i)

Answer 2

You logic here

for (i = 3; i <= 1; --i) {
     System.out.println(i);
}

is

a) start with i being three

b) if i <= 1
   then print
   decrement i

c) loop again

Obviously the loop will never be entered into

try

for (i = 3; i >= 1; --i) {
     System.out.println(i);
}

Answer 3

You should write you code like:

public class ForLoops {
    public static void main (String [] args) {

       int firstNumber;
       int i;

       firstNumber = 3;

       for (i = firstNumber; i >= 1; --i) {
          System.out.println(i);
       }
   }
}

Answer 4

You have simple mistake in for loop condition.

Shouldn't it be greater than or equal to (>=) as you are going in reverse direction.

change it to:

for (i = 3; i >= 1; --i)

Answer 5

Your mistake seems to be, that you used a <= (smaller or equal) which is never true (3 can never be smaller or equal to 1). So you have to use a >=

And you can't have space in the name of your variable ( int first Numer; has to be int firstNumer;)

public class Test{
    public static void main(){
         int firstNumber;
         firstNumber = 3;

         for(int i = 3; i >= 1; i--){
              System.out.println(i);
         }
    }
}

Sorry for my bad spelling, but I am on my phone right now. I hope I could help you.

Answer 6

this is correc code:

   public class ForLoops {
    public static void main (String [] args) {
      int firstNumber;
      int i;

      firstNumber = 3;

      i = firstNumber;   

      for (i = 3; i <= 1; --i) {
         System.out.println(i);
     }
   }
}