A **for-loop** is a control flow statement which is used to execute a block of code a number of times. The flow of the for-loop is specified after each execution of the code block (called an *iteration*). 



Imagine a situation where you have to do a certain task a hundred times. How would you do that? You could type the command to achieve the task a hundred times, or maybe copy-paste it repeatedly. 

Of course, that would be quite tedious. This is where loops come into use. When using a *for-loop*, those hundred lines of code can be written in as few as three to four statements.


# Syntax

This is what a for-loop looks like in JavaScript:

/* for-loop syntax in JavaScript */
for (variable_initialize; condition; change_variable) {
  // code block to be executed
}

# Arguments

- **`variable_initialize`** (*optional*): This statement is executed once before the execution of the `for-loop` code block. This is used to define the counter variable etc. you might be using to control the flow.

- **`condition`:** This statement defines the condition on which the control flow (each iteration) of the `for-loop` depends.

- **`change_variable`:** This statement is executed after each iteration of the `for-loop`. This can be used to update the initialized control variable.

> **Note:** `variable_initialize` is *optional* since you can use an already initialized variable instead. Do not forget the `;` following the `variable_initialize` even if you decide to skip it!

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# Flow Diagram

# Examples

This code will print out the incremented `temp` variable from `0` through `4`, with an updated value in each iteration, followed by the word `: Educative!`. The *expanded* version for the same code is also given in the second code tab, which should be helpful in understanding how exactly the `for-loop` executes.

for (var temp = 0; temp < 5; temp++) {
  // Runs 5 times, with values of temp 0 through 4.
  console.log(temp + ": Educative!");
}

for-loop

var temp = 0;                       //varialble_initialize (runs once)
console.log(temp + ": Educative!"); //- condition satisfies
temp = 1;                               //- variable incremented
console.log(temp + ": Educative!");
temp = 2;
console.log(temp + ": Educative!");
temp = 3;
console.log(temp + ": Educative!");
temp = 4;                               //-
console.log(temp + ": Educative!"); //- condition breaks

How to execute a for-loop in JavaScript

Syntax

Arguments

Flow Diagram

Examples