For loops in Java

In Java, a `for` loop is a control flow statement that allows you to repeatedly execute a block of code based on a specific condition. The `for` loop is especially useful when you know the number of iterations in advance. Let's break down the components of a `for` loop and explore its syntax and usage.

### Syntax:

The basic syntax of a `for` loop in Java is as follows:

```java

for (initialization; condition; update) {

    // code to be executed

}

```

- **Initialization:** This is where you initialize the loop control variable. It is executed only once at the beginning of the loop.

- **Condition:** It is a boolean expression that determines whether the loop should continue executing or not. If the condition is true, the loop continues; otherwise, it exits.

- **Update:** This part is responsible for updating the loop control variable. It is executed after each iteration of the loop.

- **Code to be executed:** This is the block of code that gets executed repeatedly as long as the condition is true.

### Example:

Let's consider a simple example where we want to print numbers from 1 to 5 using a `for` loop:

```java

public class ForLoopExample {

    public static void main(String[] args) {

        // Loop to print numbers from 1 to 5

        for (int i = 1; i <= 5; i++) {

            System.out.println(i);

        }

    }

}

```

In this example:

- **Initialization (`int i = 1`):** We initialize the loop control variable `i` to 1.

- **Condition (`i <= 5`):** The loop will continue as long as `i` is less than or equal to 5.

- **Update (`i++`):** After each iteration, `i` is incremented by 1.

The output of this program will be:

```

1

2

3

4

5

```

### Multiple Initialization and Update Statements:

You can also have multiple initialization and update statements separated by commas. For example:

```java

for (int i = 1, j = 5; i <= 5; i++, j--) {

    // code to be executed

}

```

### Enhanced for Loop (for-each Loop):

In addition to the traditional `for` loop, Java also provides an enhanced version, often referred to as the "for-each" loop, which simplifies iteration through collections or arrays. Here's an example:

```java

int[] numbers = {1, 2, 3, 4, 5};

for (int num : numbers) {

    System.out.println(num);

}

```

This loop iterates over each element in the `numbers` array and prints its value.

### Conclusion:

The `for` loop in Java is a powerful construct for iterating over a range of values or elements in an array. It provides a concise and readable way to express repetitive tasks, making your code more efficient and maintainable.

Here are five introductory-level assignments on Java `for` loops:

### Assignment 1: Print Numbers in a Range

Write a Java program that uses a `for` loop to print the numbers from 1 to 10. The output should look like:

```

1

2

3

4

5

6

7

8

9

10

```

### Assignment 2: Calculate the Sum

Create a Java program that calculates and prints the sum of the first 100 natural numbers using a `for` loop. The output should display the result like:

```

The sum of the first 100 natural numbers is: 5050

```

### Assignment 3: Multiplication Table

Write a Java program to generate the multiplication table for a given number (e.g., 5) using a `for` loop. The output should look like:

```

Multiplication table for 5:

5 x 1 = 5

5 x 2 = 10

5 x 3 = 15

...

5 x 10 = 50

```

### Assignment 4: Factorial Calculation

Create a Java program to calculate and print the factorial of a given number (e.g., 7) using a `for` loop. The output should be like:

```

The factorial of 7 is: 5040

```

### Assignment 5: Draw a Pattern

Write a Java program that uses nested `for` loops to draw a pattern. For example, you can create a pattern like an inverted right-angled triangle:

```

*****

****

***

**

*

```

 

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