Java For Loop

Java For Loop

When you know exactly how many times you want to loop through a block of code, use the for loop instead of a while loop.

Syntax:

for (statement 1; statement 2; statement 3) {
  // code block to be executed
}

• Statement 1 is executed (one time) before the execution of the code block.
• Statement 2 defines the condition for executing the code block.
• Statement 3 is executed (every time) after the code block has been executed.

Standard for Loop

The example below will print the numbers 0 to 4.

public class Main {
  public static void main(String[] args) {
    for (int i = 0; i < 5; i++) {
      System.out.println(i);
    }
  }
}

Example explained:

• Statement 1 sets a variable i to 0 before the loop starts.
• Statement 2 defines the condition for the loop to run (i must be less than 5). If the condition is true, the loop will start over again, if it is false, the loop will end.
• Statement 3 increases the value of i by 1 (i++) each time the code block in the loop has been executed.

For-Each Loop (Enhanced For Loop)

There is also a "for-each" loop, which is used exclusively to loop through elements in an array (or other collections).

Syntax:

for (type variableName : arrayName) {
  // code block to be executed
}

The following example outputs all elements in the cars array, using a "for-each" loop.

public class Main {
  public static void main(String[] args) {
    String[] cars = {"Volvo", "BMW", "Ford", "Mazda"};
    for (String car : cars) {
      System.out.println(car);
    }
  }
}

The for-each loop is generally more readable and less error-prone than a standard for loop when you just need to iterate over all elements of a collection.