Flash cards
Review the key moves
1/4
Core idea
What is the main idea behind Java How To Reverse a Number?
Lesson checks
Practice each idea before moving on
Short Mimo-style checks built from this lesson's code, terms, and sequence.
1Quick choice
Which statement best captures the main point of this lesson?
2Fill blank
Complete the missing token from the example code.
___ num = 1234;Reverse a Number
Take an integer and print it in reverse order:
Example
int num = 1234;
int reversed = 0;
while (num != 0) {
int digit = num % 10;
reversed = reversed * 10 + digit;
num /= 10;
}
System.out.println("Reversed: " + reversed);Explanation: We start with the number 1234 . Inside the loop: - num % 10 gives us the last digit (4, then 3, then 2, then 1). - We add this digit to reversed , making the new number grow step by step. - num /= 10 removes the last digit from the original number. When the loop finishes, reversed contains 4321 .