Loops

Question 1

What are loops?

Answer 1

Way of repeating action N times

Question 2

What are the three main types of loops in JS?

Answer 2

• For
• While
• Do while

Question 3

Example of for loop?

Answer 3

for (let i = 1; 1 < 5; i++) {
console.log(i)
}

Question 4

What 3 elements are in a “for loop”?

Answer 4

InitialExpression = where loop start
conditionExpression = where loop end
IncrementExpression = how much it goes up or down by

Question 5

What does the “i” stand for in a loop?

Answer 5

It stand for increment

Question 6

How can you describe with words the following loops?

for (let i = 1; i < 5; i++) {
    consol.log(i)
}

Answer 6

• The loop starts at let=1
• At the end of the first cycle the the loops check if 1 is < than 5 which is true
• So it does what is inside the curly braces
• Then when done it does the “i++”
• And so on until i is not longer less than 5

Question 7

Make a function that prints “21” 21 times

Answer 7

function 21(){
    for(let 1 = 1; 1 < 22; i++){
      consol.log("21")
    }
}
 21()

Question 8

How to put something into the doms (document)?

Answer 8

document.querySelector(“#id”).innertext

Question 9

How is the syntax of a while loop?

Answer 9

let count = 0

while(count < 5){
console.log(count)
count++
}

Question 10

What is the syntax for a Do while loop?

Answer 10

do {
    // loop body
  } while (condition);

Question 11

How can a part of the For loop be skipped?

Answer 11

yes by just leaving the space for (; i < 3; i++)

Question 12

What happen when we run this loop?
for (;;) {
…
}

Answer 12

it will repeat witout limits

Question 13

What are the differences between the 3 different type of loops?

Answer 13

while – The condition is checked before each iteration.
do..while – The condition is checked after each iteration.
for (;;) – The condition is checked before each iteration, additional settings available.

Question 14

What is the latest value alerted by this code?
let i = 3;

while (i) {
alert( i– );
}

Answer 14

Every loop iteration decreases i by 1. The check while(i) stops the loop when i = 0.