Loops

for

for (let counter = 0; counter < 4; counter++) {
  console.log(counter);
}
//0 1 2 3 

Looping in Reverse

for문을 -- 을 이용해서 감소하는 반복문을 작성해봅시다.

• 3 2 1 0 을 출력해봅시다.

for (let counter = 3; counter >= 0; counter--){
  console.log(counter);
}

Looping through Arrays

array에서 .length 를 이용해서 반복문을 작성해봅시다.

• 배열 인덱스는 1이 아닌 0 부터 시작한다는 점!

const vacationSpots = ['Bali', 'Paris', 'Tulum'];

for(let i = 0 ; i< vacationSpots.length;i++){
  console.log(`I would love to visit ${vacationSpots[i]}`);

}

• 결과
  I would love to visit Bali
  I would love to visit Paris
  I would love to visit Tulum

Nested Loops

이중 for 문을 작성해봅시다.

for (let outer = 0; outer < 2; outer += 1) {
  for (let inner = 0; inner < 3; inner += 1) {
    console.log(`${outer}-${inner}`);
  }
}

/* 
Output:
0-0
0-1
0-2
1-0
1-1
1-2
*/

The While Loop

// A for loop that prints 1, 2, and 3
for (let counterOne = 1; counterOne < 4; counterOne++){
  console.log(counterOne);
}

// A while loop that prints 1, 2, and 3
let counterTwo = 1;
while (counterTwo < 4) {
  console.log(counterTwo);
  counterTwo++;
}

Do...While Statements

while : 조건 확인 후 loop -> 조건이 거짓일 경우 실행 x

do-while : 실행한 뒤 조건이 충족이 되는지 확인 후 loop -> 즉 1번은 무조건 실행

const firstMessage = 'I will print!';
const secondMessage = 'I will not print!'; 

// A do while with a stopping condition that evaluates to false
do {
 console.log(firstMessage)
} while (true === false);

// A while loop with a stopping condition that evaluates to false
while (true === false){
  console.log(secondMessage)
};