While Loops

While Statement Loops

It is possible for a while loop to stand without the do. Including the do guarantees that the statement inside the while will process once. It is wise to take care with stand-alone while loops, as they have a natural tendency to go infinite.

The while loop executes its statements if the designated condition (i.e. n < 3) reads as TRUE. If the condition reads FALSE, the statement within the loop stops executing and control passes on. The condition is checked before the statement (i.e. n++; x += n;) is executed, at which point, the condition is checked again. If the condition returns FALSE, execution stops and control passes on before the statement is executed. To execute multiple statements, use a block statement ({...}) to group.

//While Loops

//Create a variable
var score = 0;
        //Set a condition in parens
while(score < 10){
    //Set an increment operation
    score++;
    //Print to the console
    console.log("Score: ", score);
}

//Another example
var age = 0;
while(age < 100){
    age+=10;
    console.log("Age:", age);
}

if (age === 100){
    console.log("I made it!");
}

//A challenge -create a while loop that prints 10-100 by 10s. AT 50
// print "Halfway there!"

var counter = 0;
while(counter < 100){
    counter+=10;
    if(counter === 50){
        console.log("There's halfway");
    } else {
        console.log(counter);
    }
}

Difference Between For and While Loops

// for loop

var cars = ['BMW', 'Volvo', 'Saab', 'Ford'];
var i = 0;
var text = '';

for (;cars[i];) {
  text += cars[i] + '<br>';
  i++;
}

// while loop

var cars = ['BMW', 'Volvo', 'Saab', 'Ford'];
var i = 0;
var text = '';

while (cars[i]) {
  text += cars[i] + '<br>';
  i++;
}