Why there is no output or blank output for this java code containing “do while” loop? [closed]

问题

Can you please explain why there is no output or blank output for the following java code containing do while loop?

public class Main
{
    public static void main(String[] args) {
        int i = 10; 
        do while ( i < 10 )
        System.out.print("The value of i is " + i); 
        while ( i > 10 ) ; 
        
    }
}

回答1:

it doesn't run this:

do while ( i < 10 )

because of this:

i = 10;

回答2:

First, a do while loop works as follows:

do {
    // code...
} while(condition);

And this loop executes the code in the brackets as long as the condition is evaluated to true.

Second, in your code the condition is false, because i is not less than 10.

A fix would probably look something like this:

int i = 0;
do {
   i++;
   System.out.print("The value of i is " + i + "\n");
} while ( i < 10 );

All depending by the wanted logic.

回答3:

That is the incorrect syntax for a do-while loop. Try the following code.

 int i = 10
 do {
    System.out.println("The value of i is " + i);
 } while (i > 10);

You only need the while statement at he end and curly braces after the do statement like this

do {
} while (expression);

Even with the correct syntax nothing will print because i is 10 and the do-while loop only runs when i is more than 10.

回答4:

Your code, with appropriate braces, looks like this

int i = 10; 
do
{
    while ( i < 10 )
    {
        System.out.print("The value of i is " + i);
    }
}
while ( i > 10 );

i is exactly 10, which is not greater than or less than 10, so neither condition is satisfied.

You also never update the value of i so even if one of the conditions were satisfied, your program would enter an infinite loop.

来源：https://stackoverflow.com/questions/63451780/why-there-is-no-output-or-blank-output-for-this-java-code-containing-do-while

标签

java

loops

do-while