Swap two Strings without using third user defined variable in Java
Given two string variables a and b, swap these variables without using temporary or third variable in Java. Use of library methods is allowed.
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:
- substring(int beginindex): This function will return substring of the calling string starting from the index passed as argument to this function till the last character in the calling string.
- substring(int beginindex,int endindex): This function will return Substring of the calling string starting from the beginindex(inclusive) and ending at the endindex(exclusive) passed as argument to this function.
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());
Strings before swap: a = Hello and b = World Strings after swap: a = World and b = Hello
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