Nested loop in Java

A nested loop in Java is a loop within a loop. It allows you to iterate over a set of statements multiple times, where each iteration of the outer loop can have its own set of iterations in the inner loop. The basic syntax of a nested loop in Java is as follows:

for (int i=1; i<=outer; i++) {
   for (int j=1; j<=inner; j++) {
      statement(s);
   }
}

The outer loop is represented by the first for loop, and the inner loop is represented by the second for loop. The statements inside the inner loop are executed for each iteration of the outer loop.

Nested loops are useful in scenarios where you need to perform a certain operation multiple times, where each iteration of the outer loop has its own set of operations in the inner loop. For example, consider a scenario where you want to print the multiplication table for numbers from 1 to 10. You can use a nested loop to achieve this:

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

In this example, the outer loop iterates over the numbers from 1 to 10, and the inner loop iterates over the numbers from 1 to 10. For each iteration of the outer loop, the statements inside the inner loop are executed, which calculates and prints the product of the two numbers.

Nested loops can also be used to iterate over two-dimensional arrays, where each iteration of the outer loop corresponds to a row, and each iteration of the inner loop corresponds to a column. For example, consider the following two-dimensional array:

int[][] numbers = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
for (int i=0; i<numbers.length; i++) {
   for (int j=0; j<numbers[i].length; j++) {
      System.out.print(numbers[i][j] + " ");
   }
   System.out.println();
}

In conclusion, nested loops in Java allow you to perform a set of operations multiple times, where each iteration of the outer loop can have its own set of iterations in the inner loop. They are useful in scenarios where you need to perform a certain operation multiple times, where each iteration of the outer loop has its own set of operations in the inner loop. Understanding when and how to use nested loops is an important aspect of programming in Java.