在Java中的if语句中的while循环

Question

while loop is not working in the if statement, why its not working... and how can while loop can work in if curly braces.

public static void main(String[] args) {
    int x = 30;

    if (x < 20) {
        System.out.print("This is if statement");         
        int a = 10;
        while(a < 20) {
            System.out.print("value of x : " + a );
            a++;
            System.out.print("\n");
        } 
    } else {
        System.out.print("This is else statement");
    }        
}

Answer 1

You declared x as 30, the if loop executes if(x<20) which is always false, so its performing the else statement immediately without going thru the if statement. You either have to declare x for something less than 20 or change the if statement.

Answer 2

Your if statement doesn't meet the condition. Try this:

public static void main(String[] args) {
    // TODO code application logic here

    int x = 10;

    if( x < 20 ) {
    System.out.print("This is if statement");         
      int a = 10;
    while( a < 20 ) {
     System.out.print("value of x : " + a );
     a++;
     System.out.print("\n");
  }


  }else {
     System.out.print("This is else statement");
  }

}

And output:

This is if statementvalue of x : 10
value of x : 11
value of x : 12
value of x : 13
value of x : 14
value of x : 15
value of x : 16
value of x : 17
value of x : 18
value of x : 19

Answer 3

您为x分配的值是30，但是在您的条件下要检查x小于20，因此条件将失败并且将无法执行...