Code7 - Stage 10

Conditionals

Gary Dalton

16 July 2015

Fork on GitHub

Conditionals

Conditionals are the way computers make decisions. Conditionals are used in if-statements and loops.

Objective

  • Gain experience determining the outcome (true or false) of conditionals
  • Evaluate logical statements to determine which branch of a program to follow
  • Introduced to javascript code

Materials

  • Blank paper for keeping score
  • One deck of playing cards

Vocabulary

  • Conditional: A statement that is either true or false depending on the situation
  • If Statement: A line that determines whether or not you run a certain chunk of code
  • Else: Another way of saying "Otherwise"
  • Function: A piece of code that can be called over and over
  • Increment: To add a certain amount (often 1), once or many times
  • Decrement: To subtract a certain amount (often 1), once or many times

  • Nested Statements: A statement inside another statement

    • Review and Extend

    • How is a while block different from an if block?
    • Can you think of anything we do in real life that could be described with a while loop?

    Simple If

    If you all raise your hand,
    I will clap.

    If with Else

    If you all raise your hand,
    I will clap.
Else,
    I will touch my nose.

    Nested If-Else

    If you all stand,
    I will bark.
    If you all clap,
        I will stand on 1 foot.
    Else,
        I will stand on both feet
Else,
    I will whistle.

    If, Else if, and Else

    If you all touch your ear,
    I will mew.
Else if you all touch your nose,
    I will moo.
Else,
    I will whistle.

    Conditionals

    We call these "If Statements" conditionals, because there is a condition placed on them. Something is either true, or it's not. If it's true, we do the instruction inside the "If Statement". Otherwise, we do the instruction inside of the "Else Statement".

    Questions?

    Activity

    We will use a deck of cards and conditional statements to score points.

    This is the conditional code in javascript.

    if (card.color == black){
    team.points += 1;
}
else{
    team.points -=1;
}

    Javascript Pseudocode
    if (card.color == black){ if card’s color is black
    team.points += 1; then team’s points increase by 1
    }
    else{ otherwise
    team.points -=1; team’s points decrease by 1
    }

    • Yes, the parentheses, brackets, and semicolons are required
    • '==' means check if it equals while '=' sets it equal
    • '+=' means increment
    • '-=' means decrement

    Ok, let's score points

    if (card.color == black){
    team.points += 1;
}
else{
    team.points -=1;
}

    Try with different algorithm

    while (card.value < 5){
    team.points ++;
    if (card.value == 3){
        team.points += 2;
        if(card.suit == "clubs"){
            team.points --;
        }
    }
}

    Write a simple card-scoring conditional algorithm in javascript

    Objectives

    • How do computers make decisions?
    • On code.org, you can see the javascript of your code by clicking "</> Show Code"

    Vocabulary

    • Conditional: A statement that is either true or false depending on the situation
    • If Statement: A line that determines whether or not you run a certain chunk of code
    • Else: Another way of saying "Otherwise"
    • Function: A piece of code that can be called over and over
    • Increment: To add a certain amount (often 1), once or many times
    • Decrement: To subtract a certain amount (often 1), once or many times
    • Nested Statements: A statement inside another statement

    Mark Stage 10 as complete on code.org