What is the rule for nested loop code?

Question

I am new to programming and currently learning Java from Stanford free learning course. There was this assignment that I had trouble translating my algorithm into code. I feel like I have a misconception about nested loops.

My question in this code:

while (frontIsClear()) {   //LET THIS REFER AS BOOLEAN 1
  putBeeper();             //LET THIS REFER AS STAT 1
  if (frontIsClear()) {    // LET THIS REFER AS BOOLEAN 2
    move();                //LET THIS REFER AS STAT 2
  }
}

If BOOLEAN 1 is TRUE but BOOLEAN 2 is FALSE then will STAT 1 work or will it terminate everything?
I understand STAT 2 won't work because BOOLEAN 2 is false but I just don't get this loop inside condition etc.

Answer 1

Every loop in Java (and most, but not all programming languages) has a loop conditional which is checked every iteration. It works just like an if statement: the conditional is a boolean expression. If it evaluates to true, the loop executes. If it evaluates to false, the loop stops and control flows to the next statement after the loop.

In this code, frontIsClear() is used to control both the while loop and the if conditional. If the method returns false in either case, the body of that construct (compound statement, everything between { and }) will not execute.

Answer 2

It Depends... If your putBeeper() method has any impact on this condition; frontIsClear(), it will not call to move() method if the conditional statement becomes false.

In your given example, there are no nested loops. For example:

int i = 0;
while (frontIsClear()) {
 putBeeper();
 while (i<3) {
  move();
 }
}

So you'll move 3 steps when frontIsClear().