Looping. Why is this happening? Prime Numbers - numbers

Question

I'm having a problem understanding the looping, when I put the System.out.println("Looping: " + i); at the start of the for in method.
It loops three times, more than usual, for example with the number 13, it says:
Looping: 2 , Looping: 2, Looping 3.
But instead if I put System.out.println("Looping: " + i); at the end of the for in method, it appears:
Looping 2, Loopin 3
which is the more accurate to my understanding.
Why is this happening?
public static void main(String[] args) {
int counter = 0;
for(int i=1; i <= 10; i++){
if(isPrime(i)){
System.out.println("The number: " + i + " is a prime number");
counter++;
}
if(counter==3){
break;
}
}
public static boolean isPrime(int n){
if(n == 1){
return false;
}
for(int i=2; i <= (long) Math.sqrt(n); i++){
System.out.println("Looping: " + i);
if(n%i == 0){
return false;
}
}
return true;
}

Answer 1

Let take this code:
public static boolean isPrime(int n){
if(n == 1){
return false;
}
for(int i=2; i <= (long) Math.sqrt(n); i++){
System.out.println("Looping: " + i); // first
if(n%i == 0){
return false;
}
System.out.println("Looping2: " + i); // second
}
return true;
}
It's output is:
Looping: 2
Looping: 2
Looping2: 2
As you see the first System.out.println is 2 times executed and the second only once. It happens because of
if(n%i == 0){
return false;
}
If n%i == 0 gives true then the method will return false and for loop stops executing. This explains why it makes difference where to put System.out.println.
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