Problems

1. Operators

Why both print same values?

for (i = 0;i<10;i++) {
  System.out.print(i);
}
System.out.println();
for (i=0;i<10;++i) {
  System.out.print(i);
}

// 0123456789
// 0123456789

Both i++ and ++i increment the value of i by 1, but the difference lies in when the increment happens in expressions — not in loops like for where the value isn't used during increment.

• i++ → Post-increment: Increments i after the value is used

• ++i → Pre-increment: Increments i before the value is used

But in a for loop:

for (i = 0; i < 10; i++)  // or ++i

The increment expression (i++ or ++i) happens after each iteration, and its return value is not used anywhere in the loop control itself.

So both loops behave the same:

1. Initialize i = 0

2. Check condition i < 10

3. Execute System.out.print(i)

4. Increment i (post or pre — doesn’t matter because value isn't used)

5. Repeat

If we wrote something like:

int x = i++;
int y = ++i;

Here, the difference matters:

• x = i++: assigns the value of i to x, then increments i

• y = ++i: increments i, then assigns the new value to y