Input: a = "Hello" b = "World" Output: Strings before swap: a = Hello and b = World Strings after swap: a = World and b = Hello
The idea is to string concatenation and substring() method to perform this operation. The substring() method comes in two forms as listed below:
1) Append second string to first string and store in first string: a = a + b 2) call the method substring(int beginindex, int endindex) by passing beginindex as 0 and endindex as, a.length() - b.length(): b = substring(0,a.length()-b.length()); 3) call the method substring(int beginindex) by passing b.length() as argument to store the value of initial b string in a a = substring(b.length());
// Java program to swap two strings without using a temporary // variable. import java.util.*; class Swap { public static void main(String args[]) { // Declare two strings String a = "Hello"; String b = "World"; // Print String before swapping System.out.println("Strings before swap: a = " + a + " and b = "+b); // append 2nd string to 1st a = a + b; // store initial string a in string b b = a.substring(0,a.length()-b.length()); // store initial string b in string a a = a.substring(b.length()); // print String after swapping System.out.println("Strings after swap: a = " + a + " and b = " + b); } }
Output:
Strings before swap: a = Hello and b = World Strings after swap: a = World and b = Hello