C# | Swap two Strings without using third user defined variable
Given two string variables a and b, swap these variables without using a temporary or third variable in C#. 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 do string concatenation and then use Substring() method to perform this operation. The Substring() method comes in two forms as listed below:
- String.Substring Method (startIndex): This method is used to retrieve a substring from the current instance of the string. The parameter “startIndex” will specify the starting position of substring and then substring will continue to the end of the string.
- String.Substring Method (int startIndex, int length): This method is used to extract a substring that begins from specified position described by parameter startIndex and has a specified length. If startIndex is equal to the length of string and parameter length is zero, then it will return nothing as substring.
1) Append second string to first string and store in first string: a = a + b 2) Call the Substring Method (int startIndex, int length) by passing startindex as 0 and length as, a.Length - b.Length: b = Substring(0, a.Length - b.Length); 3) Call the Substring Method(int startIndex) by passing startindex as b.Length as the argument to store the value of initial b string in a a = Substring(b.Length);
Strings before swap: a = Hello and b = Geeks Strings after swap: a = Geeks and b = Hello