Java For Loop

Java For Loop: Definition and Basics

• Initialization: Here, you set a starting point.
• Condition: This is the test that needs to pass for the loop to run.
• Iteration: The process update that occurs with each loop.

for (int i = 0; i < 10; i++) {
    System.out.println(i);
}

Insights into the Java For Loop Technique

Differentiating Between Java For Loop and Other Loop Structures

Applying the Java For Loop Syntax

Starting with Java For Loop Syntax Basics

• Initialisation: In the initialisation part, you can declare and initialise the loop control variable, which is commonly an integer. This variable will be used to control how many times the loop gets executed. For instance, if you write

  int i = 0;

  This means that the loop control variable 'i' starts at 0.
• Condition: The condition is the test performed to decide whether the loop will execute or not. We test the loop control variable against a certain condition, and as long as this condition is true, the loop will continue.

  i < 10;

  In this example, the loop will keep executing as long as variable 'i' is less than 10.
• Iteration: After each time the loop is executed, the loop control variable is updated. Mostly, we either increment or decrement the loop control variable. This update happens after each iteration of the loop. If you write

  i++;

  This means that after each iteration, the variable 'i' is incremented by 1.

Importance of Correct Java For Loop Syntax

• Forgetting to initialise the control variable

   for (; i < 10; i++); 

  This loop results in a compile-time error because control variable is not initialised.
• Misspelling keywords or names of variables

   for (int I = 0; I < 10; i++); 

  This loop leads to a compile-time error because 'I' (upper case) is not the same as 'i' (lower case).
• Using wrong comparison operator

   for (int i = 0; i > 10; i++); 

  This loop won't execute because 'i' is initially less than 10 but the condition is waiting for 'i' to be greater than 10.

Variations of Java For Loop

Introduction to For Each Loop Java

int[] nums = {1, 2, 3, 4, 5};
for (int num : nums) {
    System.out.println(num);
}

Understanding the Enhanced For Loop Java

Mastering the Nested For Loops Java

int[][] grid = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
for (int row = 0; row < grid.length; row++) {
    for (int col = 0; col < grid[row].length; col++) {
        System.out.print(grid[row][col] + " ");
    }
    System.out.println(); // This prints a new line between each row.
}

Working with Java For Loop Array

Basics of Java For Loop Array

int[] numbers = {1, 2, 3, 4, 5};
for (int i = 0; i < numbers.length; i++) {
    System.out.println(numbers[i]);
}

Practical Java For Loop Array Examples

int[] numbers = {10, 20, 30, 40, 50};
int sum = 0;

for (int i = 0; i < numbers.length; i++) {
    sum += numbers[i];
}

double average = (double) sum / numbers.length;
System.out.println("The average is: " + average);

int[] numbers = {2, 14, 6, 8, 20};
int max = numbers[0];
int min = numbers[0];

for (int i = 1; i < numbers.length; i++) {
    if (numbers[i] > max) {
        max = numbers[i];
    }
    if (numbers[i] < min) {
        min = numbers[i];
    }
}

System.out.println("The maximum value is: " + max);
System.out.println("The minimum value is: " + min);

Practical Java For Loop Examples

Simple Java For Loop Examples

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

for (int i = 5; i >= 1; i--) {
    System.out.println(i);
}

int sum = 0;
for (int i = 1; i <= 10; i++) {
    sum += i;
}
System.out.println("The sum is: " + sum);

Advanced Java For Loop Example Exploration

int n = 10;
int a = 0, b = 1;

System.out.println("First " + n + " numbers in Fibonacci series: ");

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

    int sum = a + b;
    a = b;
    b = sum;
}

int num = 29;
boolean prime = true;

for (int i = 2; i <= Math.sqrt(num); ++i) {
    if (num % i == 0) {
        prime = false;
        break;
    }
}

if (prime) {
    System.out.println(num + " is a prime number.");
} 
else {
    System.out.println(num + " is not a prime number.");
}

int num = 5;
long factorial = 1;
for (int i = 1; i <= num; ++i) {
    factorial *= i;
}
System.out.println("Factorial of " + num + " = " + factorial);