How to Implement Insertion Sort in Java: Step-by-Step Guide
Posted on : June 13, 2025
By
Tech World Times
Uncategorized
Rate this post
Sorting is important in programming. It helps organize data. Sorting improves performance in searching, analysis, and reporting. There are many sorting algorithms. One of the simplest is Insertion Sort.
In this article, we will learn how to implement Insertion Sort in Java. We will explain each step in simple words. You will see examples and understand how it works.
What Is Insertion Sort?
Insertion Sort is a simple sorting algorithm. It works like how you sort playing cards. You take one card at a time and place it in the right position. It compares the current element with those before it. If needed, it shifts elements to the right. Then, it inserts the current element at the correct place.
How Insertion Sort Works
Let’s understand with a small list:
Example List:Steps:
First elementis already sorted.
Compare 3 with 8. Move 8 right. Insert 3 before it →Compare 5 with 8. Move 8 right. Insert 5 after 3 →Compare 1 with 8, 5, 3. Move them right. Insert 1 at start →Now the list is sorted!
Why Use Insertion Sort?
Insertion Sort is simple and easy to code. It works well for:
Small datasets
Nearly sorted lists
Educational purposes and practice
However, it is not good for large datasets. It has a time complexity of O.
Time Complexity of Insertion Sort
Best Case: OAverage Case: OWorst Case: OIt performs fewer steps in nearly sorted data.
How to Implement Insertion Sort in Java
Now let’s write the code for Insertion Sort in Java. We will explain each part.
Step 1: Define a Class
javaCopyEditpublic class InsertionSortExample {
// Code goes here
}
We create a class named InsertionSortExample.
Step 2: Create the Sorting Method
javaCopyEditpublic static void insertionSort{
int n = arr.length;
for{
int key = arr;
int j = i - 1;
while{
arr= arr;
j = j - 1;
}
arr= key;
}
}
Let’s break it down:
arris the current value.
j starts from the previous index.
While arr> key, shift arrto the right.
Insert the key at the correct position.
This logic sorts the array step by step.
Step 3: Create the Main Method
Now we test the code.
javaCopyEditpublic static void main{
intnumbers = {9, 5, 1, 4, 3};
System.out.println;
printArray;
insertionSort;
System.out.println;
printArray;
}
This method:
Creates an array of numbers
Prints the array before sorting
Calls the sort method
Prints the array after sorting
Step 4: Print the Array
Let’s add a helper method to print the array.
javaCopyEditpublic static void printArray{
for{
System.out.print;
}
System.out.println;
}
Now you can see how the array changes before and after sorting.
Full Code Example
javaCopyEditpublic class InsertionSortExample {
public static void insertionSort{
int n = arr.length;
for{
int key = arr;
int j = i - 1;
while{
arr= arr;
j = j - 1;
}
arr= key;
}
}
public static void printArray{
for{
System.out.print;
}
System.out.println;
}
public static void main{
intnumbers = {9, 5, 1, 4, 3};
System.out.println;
printArray;
insertionSort;
System.out.println;
printArray;
}
}
Sample Output
yamlCopyEditBefore sorting:
9 5 1 4 3
After sorting:
1 3 4 5 9
This confirms that the sorting works correctly.
Advantages of Insertion Sort in Java
Easy to implement
Works well with small inputs
Stable sortGood for educational use
When Not to Use Insertion Sort
Avoid Insertion Sort when:
The dataset is large
Performance is critical
Better algorithms like Merge Sort or Quick Sort are available
Real-World Uses
Sorting small records in a database
Teaching algorithm basics
Handling partially sorted arrays
Even though it is not the fastest, it is useful in many simple tasks.
Final Tips
Practice with different inputs
Add print statements to see how it works
Try sorting strings or objects
Use Java’s built-in sort methods for large arrays
Conclusion
Insertion Sort in Java is a great way to learn sorting. It is simple and easy to understand. In this guide, we showed how to implement it step-by-step. We covered the logic, code, and output. We also explained when to use it. Now you can try it yourself. Understanding sorting helps in coding interviews and software development. Keep practicing and exploring other sorting methods too. The more you practice, the better you understand algorithms.
Tech World TimesTech World Times, a global collective focusing on the latest tech news and trends in blockchain, Fintech, Development & Testing, AI and Startups. If you are looking for the guest post then contact at techworldtimes@gmail.com
#how #implement #insertion #sort #javaHow to Implement Insertion Sort in Java: Step-by-Step Guide
Posted on : June 13, 2025
By
Tech World Times
Uncategorized
Rate this post
Sorting is important in programming. It helps organize data. Sorting improves performance in searching, analysis, and reporting. There are many sorting algorithms. One of the simplest is Insertion Sort.
In this article, we will learn how to implement Insertion Sort in Java. We will explain each step in simple words. You will see examples and understand how it works.
What Is Insertion Sort?
Insertion Sort is a simple sorting algorithm. It works like how you sort playing cards. You take one card at a time and place it in the right position. It compares the current element with those before it. If needed, it shifts elements to the right. Then, it inserts the current element at the correct place.
How Insertion Sort Works
Let’s understand with a small list:
Example List:Steps:
First elementis already sorted.
Compare 3 with 8. Move 8 right. Insert 3 before it →Compare 5 with 8. Move 8 right. Insert 5 after 3 →Compare 1 with 8, 5, 3. Move them right. Insert 1 at start →Now the list is sorted!
Why Use Insertion Sort?
Insertion Sort is simple and easy to code. It works well for:
Small datasets
Nearly sorted lists
Educational purposes and practice
However, it is not good for large datasets. It has a time complexity of O.
Time Complexity of Insertion Sort
Best Case: OAverage Case: OWorst Case: OIt performs fewer steps in nearly sorted data.
How to Implement Insertion Sort in Java
Now let’s write the code for Insertion Sort in Java. We will explain each part.
Step 1: Define a Class
javaCopyEditpublic class InsertionSortExample {
// Code goes here
}
We create a class named InsertionSortExample.
Step 2: Create the Sorting Method
javaCopyEditpublic static void insertionSort{
int n = arr.length;
for{
int key = arr;
int j = i - 1;
while{
arr= arr;
j = j - 1;
}
arr= key;
}
}
Let’s break it down:
arris the current value.
j starts from the previous index.
While arr> key, shift arrto the right.
Insert the key at the correct position.
This logic sorts the array step by step.
Step 3: Create the Main Method
Now we test the code.
javaCopyEditpublic static void main{
intnumbers = {9, 5, 1, 4, 3};
System.out.println;
printArray;
insertionSort;
System.out.println;
printArray;
}
This method:
Creates an array of numbers
Prints the array before sorting
Calls the sort method
Prints the array after sorting
Step 4: Print the Array
Let’s add a helper method to print the array.
javaCopyEditpublic static void printArray{
for{
System.out.print;
}
System.out.println;
}
Now you can see how the array changes before and after sorting.
Full Code Example
javaCopyEditpublic class InsertionSortExample {
public static void insertionSort{
int n = arr.length;
for{
int key = arr;
int j = i - 1;
while{
arr= arr;
j = j - 1;
}
arr= key;
}
}
public static void printArray{
for{
System.out.print;
}
System.out.println;
}
public static void main{
intnumbers = {9, 5, 1, 4, 3};
System.out.println;
printArray;
insertionSort;
System.out.println;
printArray;
}
}
Sample Output
yamlCopyEditBefore sorting:
9 5 1 4 3
After sorting:
1 3 4 5 9
This confirms that the sorting works correctly.
Advantages of Insertion Sort in Java
Easy to implement
Works well with small inputs
Stable sortGood for educational use
When Not to Use Insertion Sort
Avoid Insertion Sort when:
The dataset is large
Performance is critical
Better algorithms like Merge Sort or Quick Sort are available
Real-World Uses
Sorting small records in a database
Teaching algorithm basics
Handling partially sorted arrays
Even though it is not the fastest, it is useful in many simple tasks.
Final Tips
Practice with different inputs
Add print statements to see how it works
Try sorting strings or objects
Use Java’s built-in sort methods for large arrays
Conclusion
Insertion Sort in Java is a great way to learn sorting. It is simple and easy to understand. In this guide, we showed how to implement it step-by-step. We covered the logic, code, and output. We also explained when to use it. Now you can try it yourself. Understanding sorting helps in coding interviews and software development. Keep practicing and exploring other sorting methods too. The more you practice, the better you understand algorithms.
Tech World TimesTech World Times, a global collective focusing on the latest tech news and trends in blockchain, Fintech, Development & Testing, AI and Startups. If you are looking for the guest post then contact at techworldtimes@gmail.com
#how #implement #insertion #sort #java
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