Operators and Loops

Loops and iterations

Loops offer a quick and easy way to do something repeatedly.

A loop is a computerized version of the game where you tell someone to take X steps in one direction, and Y steps in another. The below is an idea to “Go five steps to the east” as a loop.

for (let step = 0; step < 5; step ++) { // Runs 5 times, with values of step 0 through 4. console.log (‘Walking east one step’); }

There are many different types of loops, but they do the same thing: repeat an action some number of times.

There are various situations that are more easily serve dby one type of loop over the others. Various loop mechanisms offer different wayt to determine the start and end points of the loop.

Statements for loops provided in JS are:

For statement

A for loop repeats until a specified condition evaluates to false. The JavaScript for loop is similar to the Java and C for loop.

While statement

A while statement executes its statements as long as a specified condition evaluates true. A while statement looks as follows:

while (condition) statement

If the condition becoms false, statement within the loop stops executing and control passes to the statement following the loop.

The condition test occurse before statement in the loop is executed. If the condition returns true, statement is executed and the condition is tested again. If the condition returns false, execution stops, and control is passed tot he statement following while.

Example

let n = 0; let x = 0; while (n < 3) { n++; x += n; }

break statement

Use the break statement to terminate a loop, switch, or in conjunction with a labeled statement.

continue statement

The continue statement can be used to restart a while, do-while, for, or label statement.

for...in statement

The for…in statement iterates a specified variable over all the enumerable properties of an object. For each distinct propert, JavaScript executes the specified statements. A for...in statement looks as follows:

for (variable in object) statement

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