# JavaScript Program to Form coils in a matrix

We will be using JavaScript to form coils in a matrix. The process involves manipulating the elements of the matrix to create a spiral pattern. This can be achieved by changing the direction of traversal, keeping track of the visited elements, and adjusting the indices accordingly. We will be continuously working on the logic to make sure that the program runs smoothly and efficiently to produce the desired output.

## Approach

One approach to form coils in a matrix using JavaScript would be the following −

• Define the size of the matrix.

• Initialize the matrix with zeros.

• Use nested loops to traverse the matrix and change the values of specific cells according to the pattern of the coil.

• Keep track of the direction of traversal (right, down, left, up) and change direction as needed.

• Use another loop to print the matrix.

• Repeat the process to form multiple coils if needed.

## Example

Here is an example of how you could implement a function in JavaScript to form coils in a matrix −

function formCoils(matrix) {
let row = 0, col = 0, direction = 'down';
for (let i = 0; i < matrix.length * matrix[0].length; i++) {
matrix[row][col] = i + 1;
if (direction === 'down') {
if (row === matrix.length - 1 || matrix[row + 1][col] !== 0) {
direction = 'right';
col++;
} else {
row++;
}
} else if (direction === 'right') {
if (col === matrix[0].length - 1 || matrix[row][col + 1] !== 0) {
direction = 'up';
row--;
} else {
col++;
}
} else if (direction === 'up') {
if (row === 0 || matrix[row - 1][col] !== 0) {
direction = 'left';
col--;
} else {
row--;
}
} else if (direction === 'left') {
if (col === 0 || matrix[row][col - 1] !== 0) {
direction = 'down';
row++;
} else {
col--;
}
}
}
return matrix;
}
const matrix = [[0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]];
console.log(formCoils(matrix));


The formCoils function takes in a matrix and returns the same matrix with numbers formed in a coil shape starting from the top left corner.

The function uses a variable direction to keep track of the direction in which the number should be filled in the matrix. It starts with direction set to 'down', and updates direction based on the current position of the matrix and whether the next position is filled or not. The number is then placed in the current position and the row and column variables are updated accordingly.

This process is repeated until every position in the matrix has been filled with a number.

Example usage −