public class ReverseNumber {
public static void main(String[] args) {
int num = 1234, reversed = 0;
while(num != 0) {
int digit = num % 10;
reversed = reversed * 10 + digit;
num /= 10;
}
System.out.println("Reversed Number: " + reversed);
}
}
When you run the program, the output will be:
Reversed Number: 4321
In this program, while loop is used to reverse a number as given in the following steps:
num != 0
fails and while loop exits. reversed already contains the reversed number 4321.
public class ReverseNumber {
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);
}
}
When you run the program, the output will be:
Reversed Number: 7654321
In the above program, the while loop is replaced by a for loop where:
num != 0
)num /= 10
.So, after each iteration, the update expression runs which removes the last digit of num.
When the for loop exits, reversed will contain the reversed number.