Swapping variable in java

Swap Two Variables in One Line

We have discussed different approaches to swap two integers without the temporary variable. How to swap into a single line without using the library function?
1) Python: In Python, there is a simple and syntactically neat construct to swap variables, we just need to write “x, y = y, x”.
2) C/C++: Below is one generally provided classical solution:

// Swap using bitwise XOR (Wrong Solution in C/C++) x ^= y ^= x ^= y;

The above solution is wrong in C/C++ as it causes undefined behavior (the compiler is free to behave in any way). The reason is, modifying a variable more than once in an expression causes undefined behavior if there is no sequence point between the modifications.
However, we can use a comma to introduce sequence points. So the modified solution is

// Swap using bitwise XOR (Correct Solution in C/C++) // sequence point introduced using comma. (x ^= y), (y ^= x), (x ^= y);

3) Java: In Java, rules for subexpression evaluations are clearly defined. The left-hand operand is always evaluated before the right-hand operand. In Java, the expression “x ^= y ^= x ^= y;” doesn’t produce the correct result according to Java rules. It makes x = 0. However, we can use “x = x ^ y ^ (y = x);” Note the expressions are evaluated from left to right. If x = 5 and y = 10 initially, the expression is equivalent to “x = 5 ^ 10 ^ (y = 5);”. Note that we can’t use this in C/C++ as in C/C++, it is not defined whether the left operand or right operand is executed by any operator (See this for more details).

4) JavaScript: Using destructing assignment, we can simply achieve swapping using this one line.

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How to Swap Values of Two Variables in Java — Techniques and Examples

Learn different techniques to swap values of two variables in Java, including code examples for swapping with a temporary variable, bitwise XOR operator, call-by-reference, and more.

• Introduction:
• 1. Swapping using a temporary variable:
• 2. Swapping without using a temporary variable:
• 3. Swapping using bitwise XOR operator:
• 4. Swapping two string variables:
• 5. Swapping two integers without using a temporary variable:
• 6. Swapping without using a third variable:
• Conclusion:
• How to swap two values in Java?
• How to swap two numbers in Java without temporary variables?
• How to swap values without using third variable?
• How do you swap values between two numbers in Python?

Swapping the values of two variables is a common task in programming. It is often used in sorting algorithms, and other programs where the order of values is important. In Java, there are various techniques for swapping two variable values, and in this article, we will explore some of them.

Introduction:

swapping two variables in java involves exchanging their values. It is a common operation in programming that can be achieved using different methods. In this article, we will explore various techniques for swapping two variable values in Java.

1. Swapping using a temporary variable:

One way to swap two variable values in Java is using a temporary variable. This method is simple and easy to understand. Here are the steps to swap two variable values using a temporary variable:

1. Create a temporary variable and assign the value of the first variable to it.
2. Assign the value of the second variable to the first variable.
3. Assign the value of the temporary variable to the second variable.

Here’s an example code snippet:

int temp; temp = a; a = b; b = temp; 

2. Swapping without using a temporary variable:

Another way to swap two variable values in Java is without using a temporary variable. This method is more efficient than using a temporary variable, as it requires fewer operations. Here are the steps to swap two variable values without using a temporary variable:

1. Add the values of the two variables.
2. Assign the difference of the sum and the first variable to the second variable.
3. Assign the difference of the sum and the second variable to the first variable.

Here’s an example code snippet:

3. Swapping using bitwise XOR operator:

Swapping two variable values in Java can also be done in one line using the bitwise XOR operator . This method is efficient and requires fewer operations. Here are the steps to swap two variable values using the XOR operator:

1. Assign the XOR of the two variables to the first variable.
2. Assign the XOR of the first variable and the second variable to the second variable.
3. Assign the XOR of the second variable and the first variable to the first variable.

Here’s an example code snippet:

4. Swapping two string variables:

The swapping process can also be applied to swapping two string variables. Here are the steps to swap two string variables using a temporary variable:

1. Create a temporary variable and assign the value of the first string to it.
2. Assign the value of the second string to the first string.
3. Assign the value of the temporary variable to the second string.

Here’s an example code snippet:

String temp; temp = str1; str1 = str2; str2 = temp; 

5. Swapping two integers without using a temporary variable:

Swapping two integers in Java can be done without using a temporary variable using the XOR trick. This method is efficient and requires fewer operations. Here are the steps to swap two integers without using a temporary variable:

1. Assign the XOR of the two integers to the first integer.
2. Assign the XOR of the first integer and the second integer to the second integer.
3. Assign the XOR of the second integer and the first integer to the first integer.

Here’s an example code snippet:

6. Swapping without using a third variable:

Swapping can be done without using a third variable by using call-by-reference. This method is more efficient than using a temporary variable, as it requires fewer operations. Here are the steps to swap two variables without using a third variable:

Here’s an example code snippet:

void swap(int &a, int &b)  a = a + b; b = a - b; a = a - b; > 

Conclusion:

Swapping two variable values in Java can be achieved using different methods. Each method has its advantages and disadvantages, and the choice depends on the situation. It is essential to test the code thoroughly and use best practices for swapping variables in java .

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How to swap variables in Java with and without a third variable

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Overview

Swapping variables means assigning the value of one variable to another programmatically. It is a very common and important operation in programming languages. In this shot, we are going to see how to swap two variables with and without the help of a third variable.

Swapping with the help of a third variable

Syntax

In the code above, a and b are the two variables that we want to swap. The third variable c will help us to swap a and b .

Code example

class HelloWorld  
public static void main( String args[] )  
// create and initialize variables
 
int no1, no2, no3;
 
no1 = 10;
 
no2 = 20;
 
// print values before swapping
 
System.out.println("Before swapping - no1: "+ no1 +", no2: " + no2);
 
// swap numbers
 
no3 = no1;
 
no1 = no2;
 
no2 = no3;
 
// print values after swapping
 
System.out.println("After swapping - no1: "+ no1 +", no2: " + no2);
 
>
>

Explanation

• Lines 4–6: We create our number variables and initialize them.
• Line 9: We print the values before swapping.
• Lines 12–14: We swap the variable values.
• Line 17: We print the swapped values.

Swapping without the help of a third variable

Syntax

To do this, we first add the values of the two variables that we want to swap and make the sum equal to a . Then we get the value of b by subtracting it from a . Finally, we get the value of a by obtaining the difference between b and the previous value of a .

int a,b;
a = a + b;
b = a - b;
a = a - b;

Code example

class HelloWorld  
public static void main( String args[] )  
// create and initialize variables
 
int no1, no2;
 
no1 = 10;
 
no2 = 20;
 
// print values before swapping
 
System.out.println("Before swapping - no1: "+ no1 +", no2: " + no2);
 
// swap numbers
 
no1 = no1 + no2;
 
no2 = no1 - no2;
 
no1 = no1 - no2;
 
// print values after swapping
 
System.out.println("After swapping - no1: "+ no1 +", no2: " + no2);
 
>
>

Explanation

• Lines 4–6: We create our number variables and initialize them.
• Line 9: We print the values before swapping.
• Lines 12–14: We swap the variable values using the method described above.
• Line 17: We print the swapped values.

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How to Swap Variables in Java With and Without a Third Variable

In Java, there can be instances where the developer needs to allocate an already assigned value to another variable as per requirements. More specifically, while dealing with the “float” or “double” values. In such situations, swapping variables in Java with and without a third variable assists in streamlining the code functionalities and utilizing the current resources effectively.

This write-up will elaborate on the approaches to swapping variables in Java with and without utilizing a third variable.

How to Swap Variables in Java With and Without a Third Variable?

To swap variables in Java using a third variable, the assignment operator “=” can be used. However, for performing the swapping without a third variable, the arithmetic operators “+” and “–” can be utilized.

Example 1: Swap Variables in Java With a Third Variable

In this example, the variables can be swapped with the help of a third variable:

public class Swap {
public static void main ( String args [ ] ) {
int value1, value2, value3 ;
value1 = 5 ;
value2 = 10 ;
System . out . println ( «The values before swapping are-> Value1: »
+ value1 + «, Value2: » + value2 ) ;
value3 = value1 ;
value1 = value2 ;
value2 = value3 ;
System . out . println ( «The values after swapping are-> Value1: »
+ value1 + «, Value2: » + value2 ) ;
} }

In the above lines of code, perform the following steps:

• Firstly, specify the three variables and initialize the stated two variables that need to be swapped and display them.
• Now, initialize the uninitialized variable, i.e., “value3” such that it becomes equivalent to the value against the variable “value1”.
• Likewise, assign the value against the variable “value2” with that of “value1”.
• Lastly, allocate the initialized value of “value3”, i.e., “5” to the variable “value2”.
• This will result in swapping the values against both variables via the variable “value3”.

In this output, it can be observed that the values against the initialized variables are swapped successfully.

Example 2: Swap Variables in Java Without Using a Third Variable

In this particular example, the variables can be swapped via the arithmetic operators “+” and “–” without any third variable:

public class Swap2 {
public static void main ( String args [ ] ) {
int value1, value2 ;
value1 = 5 ;
value2 = 10 ;
System . out . println ( «The values before swapping are-> Value1: »
+ value1 + «, Value2: » + value2 ) ;
value1 = value1 + value2 ;
value2 = value1 — value2 ;
value1 = value1 — value2 ;
System . out . println ( «The values after swapping are-> Value1: »
+ value1 + «, Value2: » + value2 ) ;
} }

According to the above code, apply the below-provided steps:

• Recall the discussed steps for initializing the default values and displaying them.
• After that, store the addition of the initialized values in the variable, i.e., “value1”.
• Similarly, return the subtraction of the assigned values firstly in the variable “value2” and then in the variable “value1”.
• Note: The subtraction in the last two cases will not yield an identical outcome since the updated value of the variables, i.e., “value1” and “value2” will be invoked in the second last and last computations, respectively.

In this outcome, it can be implied that the values are swapped accordingly regardless of the third variable.

Conclusion

To swap variables in Java with and without a third variable, the assignment operator “=” can be used. However, for performing swapping without a third variable, the arithmetic operators “+” and “–” can be utilized. Both of these approaches perform the swapping based on the updated values resulting from the computation. This blog discussed the approaches to swapping variables in Java with and without a third variable in Java.

About the author

Umar Hassan

I am a Front-End Web Developer. Being a technical author, I try to learn new things and adapt with them every day. I am passionate to write about evolving software tools and technologies and make it understandable for the end-user.

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