Java For Loop

In Java, the for loop is a control flow statement that is used to execute a block of code repeatedly for a fixed number of times. The for loop has the following syntax:

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

The initialization expression is executed only once at the beginning of the loop and is used to initialize the loop variable. The condition expression is checked before each iteration of the loop and is used to determine whether the loop should continue or terminate. The update expression is executed after each iteration of the loop and is used to update the loop variable.

Here is an example of how to use a for loop to print the numbers from 1 to 10:

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

In this example, the initialization expression initializes the loop variable i to 1, the condition expression checks whether i is less than or equal to 10, and the update expression increments i by 1 after each iteration of the loop. The output will be:

Here is another example of how to use a for loop to calculate the sum of the first 10 integers:

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

The sum of the first 10 integers is 55

Nested Loops

In Java, a nested loop is a loop inside another loop. It allows you to iterate over a set of data in a more complex pattern than a single loop could achieve.

The general syntax of a nested loop is as follows:

for (initialization; condition; update) {
    // code to be executed repeatedly
    for (inner_initialization; inner_condition; inner_update) {
        // code to be executed repeatedly
    }
}

Let’s consider the following example of a nested loop that prints out a multiplication table for numbers 1 to 10:

for(int i=1; i<=10; i++) {
    for(int j=1; j<=10; j++) {
        System.out.print(i*j + "\t");
    }
    System.out.println();
}

In this code, we have an outer loop that iterates through the numbers 1 to 10, and an inner loop that also iterates through the numbers 1 to 10. The inner loop multiplies the current value of i by j and prints the result. After each inner loop is completed, we print a new line to start a new row of the multiplication table.

The output of this code will look like:

As you can see, the nested loop allowed us to iterate through all possible combinations of i and j, and generate a table of multiplication results.

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