Java Program to Swap Two Numbers

Example 1: Swap two numbers using temporary variable

``````
public class SwapNumbers{

public static void main(String[] args){

float first = 1.20f, second = 2.45f;

System.out.println("--Before swap--");
System.out.println("First number = " + first);
System.out.println("Second number = " + second);

// Value of first is assigned to temporary
float temporary = first;

// Value of second is assigned to first
first = second;

// Value of temporary (which contains the initial value of first) is assigned to second
second = temporary;

System.out.println("--After swap--");
System.out.println("First number = " + first);
System.out.println("Second number = " + second);
}
}``````

Output:

```--Before swap--
First number = 1.2
Second number = 2.45
--After swap--
First number = 2.45
Second number = 1.2```

In the above program, two numbers `1.20f` and `2.45f` which are to be swapped are stored in variables: first and second respectively.

The variables are printed before swapping using `println()` to see the results clearly after swapping is done.

• First, the value of first is stored in variable temporary (`temporary = 1.20f`).
• Then, value of second is stored in first (`first = 2.45f`).
• And, finally value of temporary is stored in second (`second = 1.20f`).

This completes the swapping process and the variables are printed on the screen.

Remember, the only use of temporary is to hold the value of first before swapping. You can also swap the numbers without using temporary.

Example 2: Swap two numbers without using temporary variable

``````
public class SwapNumbers{

public static void main(String[] args){

float first = 12.0f, second = 24.5f;

System.out.println("--Before swap--");
System.out.println("First number = " + first);
System.out.println("Second number = " + second);

first = first - second;
second = first + second;
first = second - first;

System.out.println("--After swap--");
System.out.println("First number = " + first);
System.out.println("Second number = " + second);
}
}``````

Output:

```--Before swap--
First number = 12.0
Second number = 24.5
--After swap--
First number = 24.5
Second number = 12.0```

In the above program, instead of using temporary variable, we use simple mathematics to swap the numbers.

For the operation, storing `(first - second)` is important. This is stored in variable first.

```first = first - second;
first = 12.0f - 24.5f```

Then, we just add second (`24.5f`) to this number – calculated first (`12.0f - 24.5f`) to swap the number.

```second = first + second;
second = (12.0f - 24.5f) + 24.5f = 12.0f```

Now, second holds `12.0f` (which was initially value of first). So, we subtract calculated first (`12.0f - 24.5f`) from swapped second (`12.0f`) to get the other swapped number.

```first = second - first;
first = 12.0f - (12.0f - 24.5f) = 24.5f```

The swapped numbers are printed on the screen using `println()`.

Special 95% discount

Two Machine Learning Fields

There are two sides to machine learning:

• Practical Machine Learning:This is about querying databases, cleaning data, writing scripts to transform data and gluing algorithm and libraries together and writing custom code to squeeze reliable answers from data to satisfy difficult and ill defined questions. It’s the mess of reality.
• Theoretical Machine Learning: This is about math and abstraction and idealized scenarios and limits and beauty and informing what is possible. It is a whole lot neater and cleaner and removed from the mess of reality.

Data Science Resources: Data Science Recipes and Applied Machine Learning Recipes

Introduction to Applied Machine Learning & Data Science for Beginners, Business Analysts, Students, Researchers and Freelancers with Python & R Codes @ Western Australian Center for Applied Machine Learning & Data Science (WACAMLDS) !!!

Latest end-to-end Learn by Coding Recipes in Project-Based Learning:

Applied Statistics with R for Beginners and Business Professionals

Data Science and Machine Learning Projects in Python: Tabular Data Analytics

Data Science and Machine Learning Projects in R: Tabular Data Analytics

Python Machine Learning & Data Science Recipes: Learn by Coding

R Machine Learning & Data Science Recipes: Learn by Coding

Comparing Different Machine Learning Algorithms in Python for Classification (FREE)

`Disclaimer: The information and code presented within this recipe/tutorial is only for educational and coaching purposes for beginners and developers. Anyone can practice and apply the recipe/tutorial presented here, but the reader is taking full responsibility for his/her actions. The author (content curator) of this recipe (code / program) has made every effort to ensure the accuracy of the information was correct at time of publication. The author (content curator) does not assume and hereby disclaims any liability to any party for any loss, damage, or disruption caused by errors or omissions, whether such errors or omissions result from accident, negligence, or any other cause. The information presented here could also be found in public knowledge domains.  `