Algorithm

  1. Input: Accept the input number from the user.
  2. Initialization: Set a variable to store the reversed number, initially to 0.
  3. Processing:
    • Use a loop to extract digits from the input number one by one.
    • Multiply the reversed number by 10 and add the extracted digit to it.
    • Divide the input number by 10 to move to the next digit.
    • Repeat the process until the input number becomes 0.
  4. Output: Display the reversed number.

 

Code Examples

#1 Code Example- Reverse a Number using a while loop in Java

Code - Java Programming

class Main {
  public static void main(String[] args) {

    int num = 1234, reversed = 0;
    
    System.out.println("Original Number: " + num);

    // run loop until num becomes 0
    while(num != 0) {
    
      // get last digit from num
      int digit = num % 10;
      reversed = reversed * 10 + digit;

      // remove the last digit from num
      num /= 10;
    }

    System.out.println("Reversed Number: " + reversed);
  }
}
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Output

x
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cmd
Reversed Number: 4321

#2 Code Example- Reverse a number using a for loop in Java

Code - Java Programming

class Main {
  public static void main(String[] args) {
    
    int num = 1234567, reversed = 0;

    for(;num != 0; num /= 10) {
      int digit = num % 10;
      reversed = reversed * 10 + digit;
    }

    System.out.println("Reversed Number: " + reversed);
  }
}
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Output

x
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+
cmd
Reversed Number: 7654321
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Demonstration

Java Programing Example to Reverse a Number-DevsEnv