🔁 for loop in Java

One of the most powerful tools in Java is the for loop. Whether you want to repeat a task 10 times or process millions of records, the for loop is your go-to. 🚀

🧐 What is a for loop?

A for loop is used to execute a block of code repeatedly until a given condition is false.

👉 Syntax:

for(initialization; condition; update) {
    // Code to be executed
}

🔍 Breaking it Down

  • Initialization → Runs once, sets the starting point.

  • Condition → Checked before each loop; if false, loop stops.

  • Update → Executes after each iteration, usually increments/decrements a counter.

📌 Example:

for(int i = 1; i <= 5; i++) {
    System.out.println("Iteration: " + i);
}

💡 Output:

Iteration: 1
Iteration: 2
Iteration: 3
Iteration: 4
Iteration: 5

🎯 Why use a for loop?

✔️ Best when you know exactly how many times you want to run the loop.
✔️ Cleaner and more concise compared to while loops.
✔️ Perfect for arrays, lists, and collections.

 

⚡ Types of for loops in Java

  1. Standard for loop

    • Example above 👆

  2. Enhanced for loop (for-each loop)

    • Best for arrays & collections.

    int numbers[] = {10, 20, 30};
for(int n : numbers) {
    System.out.println(n);
}

  3. Nested for loop

    • A loop inside another loop (commonly used in patterns & matrices).

    for(int i = 1; i <= 3; i++) {
    for(int j = 1; j <= 3; j++) {
        System.out.print(i + "," + j + " ");
    }
    System.out.println();
}

Examples:

Got it 👍
Here are some popular, practical, and engaging examples of for loop in Java that you can post on your website to keep readers hooked 👇

🌟 Popular Examples of for loop in Java

1️⃣ Print Numbers from 1 to 10

for(int i = 1; i <= 10; i++) {
    System.out.print(i + " ");
}

Output:

1 2 3 4 5 6 7 8 9 10

2️⃣ Print the Multiplication Table

int num = 5;
for(int i = 1; i <= 10; i++) {
    System.out.println(num + " x " + i + " = " + (num * i));
}

Output (for 5):

5 x 1 = 5  
5 x 2 = 10  
...  
5 x 10 = 50

3️⃣ Calculate Sum of First N Numbers

int sum = 0;
for(int i = 1; i <= 100; i++) {
    sum += i;
}
System.out.println("Sum = " + sum);

Output:

Sum = 5050

4️⃣ Reverse a String

String str = "Java";
for(int i = str.length() - 1; i >= 0; i--) {
    System.out.print(str.charAt(i));
}

Output:

avaJ

5️⃣ Pattern Printing (Star Pyramid)

for(int i = 1; i <= 5; i++) {
    for(int j = 1; j <= i; j++) {
        System.out.print("* ");
    }
    System.out.println();
}

Output:

*  
* *  
* * *  
* * * *  
* * * * *

6️⃣ Iterate an Array (Using for-each loop)

int[] arr = {10, 20, 30, 40, 50};
for(int num : arr) {
    System.out.print(num + " ");
}

Output:

10 20 30 40 50

 

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