How do I swap two string variables in Java without using a third variable, i.e. the temp variable?
String a = \"one\"
String b = \"two\"
String temp = null;
temp
Jj Tuibeo's solution works if you add replaceFirst() and use a regular expression:
a += b;
b = a.replaceFirst(b + "$", "");
a = a.replaceFirst("^" + b, "");
For String Method 1:
public class SwapWithoutThirdVar{
public static void main (String args[]){
String s1 ="one";
String s2 ="two";
s1= s1+s2;
s2 = s1.substring(0,(s1.length()-s2.length()));
s1 = s1.substring(s2.length());
System.out.println("s1 == "+ s1);
System.out.println("s2 == "+ s2);
}
}
Method 2:
public class SwapWithoutThirdVar
{
public static void main (String[] args) throws java.lang.Exception
{
String s1 = "one";
String s2 ="two";
s1=s2+s1;
s2=s1.replace(s2,"");
s1=s1.replace(s2,"");
System.out.println("S1 : "+s1);
System.out.println("S2 : "+s2);
}
}
For Integers
public class SwapWithoutThirdVar {
public static void main(String a[]){
int x = 10;
int y = 20;
x = x+y;
y=x-y;
x=x-y;
System.out.println("After swap:");
System.out.println("x value: "+x);
System.out.println("y value: "+y);
}
}
String str1 = "first";
String str2 = "second";
str1 = str2+str1;
str2 = str1.substring(str2.length(),str1.length());
str1 = str1.substring(0,(str1.length() - str2.length()));
System.out.println(str1);
System.out.println(str2);
String name = "george";
String name2 = "mark";
System.out.println(name+" "+name2);
System.out.println(name.substring(name.length()) + name2 + " "+ name );
Here substring(); method returns empty string. hence , names can be appended.
The simplest way is given below:
String a = "one";
String b = "two";
System.out.println("Before swap: " a + " " + b);
int len = a.length();
a = a + b;
b = a.substring(0, len);
a = a.substring(len);
System.out.println("After swap: " a + " " + b);
Here you go. Try this:
String a = "one";
String b = "two";
//String temp=null;
int i = a.length();
a += b;
b = a.substring(0, i);
a = a.substring(i, a.length());
System.out.println(a + " " + b);
Take any value in as string in a variable. It will be swap.