Javascript Data Structure Tutorial - Javascript Repetition Statements

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Javascript while statement

To execute a set of statements when a condition is true, use the while loop.

The following code demonstrates how to use the while loop.

var number = 1; 
var sum = 0; 

while (number < 11) { 
    sum += number; 
    ++number; 
    console.log(number);
} 
console.log(sum); 

Javascript for statement

To execute a set of statements a specified number of times, use the for loop.

The following code shows how to sum integers using a for loop

var number = 1; 
var sum = 0; 

for (var number = 1; number < 11; number++) { 
    sum += number; 
    console.log(sum);
} 
console.log(sum); 

Note

for loops are used frequently to access the elements of an array, as shown in the following example.

var numbers = [31, 17, 12, 22, 100, 1, 2, 3, 4, 4, 5, 65, 6, 7, 78,999]; 
var sum = 0; 
for (var i = 0; i < numbers.length; ++i) { 
    sum += numbers[i]; 
    console.log(sum);
} 
console.log(sum);

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