Exercises in Chapter 2 of Eloquent Javascript

Chapter 2

// Exercise 2-1
// in console
// Exercise 2-2
var init = 1;
var k = 1;
while (k++ <= 10)
    init = init * 2;
print (init);
// Exercise 2-3
var str = "";
var k = 0;
while (k++ < 10) {
  str = str + "#";
print (str); 
}

// Exercise 2-4
var init = 1;
for (k = 1;k <= 10;k++)
  init = init * 2;
print (init);

var str = "";
for (k = 0;k< 10;k++) {
    str = str + "#";
    print (str);
   }

// Exercise 2-5
var num = prompt("what is 2+2");
if (num == 4)
    alert ("Good!");
else
    if (num == 3 || num == 5)
	alert ("Almost");
    else 
	alert ("Imbecile!");

// Exercise 2-6

while (true) {
    var num = prompt("what is 2+2");
    if (num == 4) {
	alert ("Good!");
	break;
    }
    else
	if (num == 3 || num == 5)
	    alert ("Almost");
	else 
	    alert ("Imbecile!");
}

// Guard and default
// okay, that's like 2.1 

// && acts as a guard which means that if the first part of 
// the test (on the left of &&) is false, 
// the second part will not execute
js> var test = false;
js> test && print ("Executing");
false
js> test = true;
true
js> test && print ("Executing");
Executing

// || provides a default if the value to the left of || is "falsy" 
js> var test = false || 3;
js> print (test);
3
js> var test = true || 4;
js> print (test);
true