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JavaScript JavaScript Basics (Retired) Making Decisions with Conditional Statements Improving the Random Number Guessing Game

Seokhyun Wie
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Seokhyun Wie
Full Stack JavaScript Techdegree Graduate 21,606 Points
Posted by Seokhyun Wie
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Seokhyun Wie
Full Stack JavaScript Techdegree Graduate 21,606 Points

Regarding the last 'if' clause

Hi Guys,

if (correctGuess) {
  document.write('<p>You guessed the number!<p>');
} else {
  document.write('<p>Sorry. The number was ' + randomNumber + ".</p>");
}

Why there's no true or false statement in the 'if' clause and just 'correctGuess' is placed?

var correctGuess = false;

this is the initial statement. And I think there should be clear declaration regarding correctGuess, but the program is working perfectly..why? Thanks.

3 Answers

Jamie Reardon
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Jamie Reardon
Treehouse Project Reviewer
Jamie Reardon
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Jamie Reardon
Treehouse Project Reviewer

Hi Brandon, the assumption that correctGuess is equal to true is because of the default behaviour of the if statement. 

// This is the same as using correctGuess == true inside the condition.
if ( correctGuess ) {
  // ...
}

// We can also override the default behaviour of the if statement by using the not (!) operator like so:
if ( !correctGuess ) { // Means if not true
  // ...
}

// Another way of doing this
if ( correctGuess !== true ) {
  // ...
}
Piotr Manczak
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Piotr Manczak
Front End Web Development Techdegree Graduate 29,365 Points
Piotr Manczak
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Piotr Manczak
Front End Web Development Techdegree Graduate 29,365 Points

Because correctGuess = true, so: correctGuess = 1, therefore it exist.

if( 1 ) { /*do something } I know it's weird. I guess we just have to accept this way of thinking. It's like a shortcut.

Seokhyun Wie
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.a{fill-rule:evenodd;}techdegree seal-36
Seokhyun Wie
Full Stack JavaScript Techdegree Graduate 21,606 Points
Seokhyun Wie
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Seokhyun Wie
Full Stack JavaScript Techdegree Graduate 21,606 Points

Hi Piotr, So do you mean that by typing only the variable ”correctGuess”, you make an assumption that it is true? Can you explain where is the assumption? Thanks.