Authors:
Stuart Reges, Marty Stepp
Chapter:
Program Logic And Indefinite Loops
Exercise:
Exercises
Question:18 | ISBN:9780136091813 | Edition: 2
Question
Write a method named swapDigitPairs that accepts an integer n as a parameter and returns a new integer whose value is similar to n’s but with each pair of digits swapped in order. For example, the call of swapDigitPairs(482596) would return 845269. Notice that the 9 and 6 are swapped, as are the 2 and 5, and the 4 and 8. If the number contains an odd number of digits, leave the leftmost digit in its original place. For example, the call of swapDigitPairs(1234567) would return 1325476. You should solve this problem without using a String.
Answer
package indefinite_loops;
public class SwapDigitPairs {
public int swapDigitPairs(int number) {
int result = 0;
int m = 1;
// as long as number is greater than zero
while( number > 0) {
int d1 = number % 10;
number /= 10;
// if num = 0 break the loop
if( number == 0) {
result += m * d1;
break;
}
// otherwise the divide the number with 10 continously
int d2 = number % 10;
result = result + m * 10 * d1 + m * d2;
number /= 10;
m *= 100;
}
// return the result
return result;
}
// driver method
public static void main(String[] args) {
// create object and call the method
SwapDigitPairs sw = new SwapDigitPairs();
System.out.println("swapped pairs of digits is: " +sw.swapDigitPairs(248657));
}
}