Assign x
To process data in our apps we need to assign values to memory locations we have previously named using var to declare a variable. Programmers read the statement "area = length * width;" as "area gets length times width". The variable getting the value always goes on the left hand side of the assignment operator =. The right hand side of the assignment operator can be a number or a string, or the number or string returned by a function, or the numeric or string result of the evaluation of an expression.
Examples
Example: assign a variable
// Declare, assign, and output the value of a variable.
var x;
x = 5;
console.log("x has the value " + x)
Example: Circumference and Area
Example: Circumference and Area Calculate the circumference and area of a circle with radius 10.
// Calculate the circumference and area of a circle with radius 10.
var radius, circumference, area;
radius = 10;
circumference = 2 * Math.PI * radius;
area = Math.PI * radius * radius;
console.log("Circle radius 10 has circumference of " + circumference + " and area of " + area);
Example: Fibonacci
Example: Fibonacci Generate the first nine terms of the Fibonacci series.
// Generate the first 9 terms of the Fibonacci series.
var termA, termB, termC;
termA = 1;
termB = 1;
termC = termA + termB;
console.log(termA + " " + termB + " " + termC);
termA = termB + termC;
termB = termC + termA;
termC = termA + termB;
console.log(termA + " " + termB + " " + termC);
termA = termB + termC;
termB = termC + termA;
termC = termA + termB;
console.log(termA + " " + termB + " " + termC);
Example: Message Board
Example: Message Board Collect, count and display messages from friends.
// Collect, count and display messages from friends.
textLabel("myTextLabel", "Type a message and press press enter");
textInput("myTextInput", "");
var count;
count=1;
onEvent("myTextInput", "change", function(event) {
var myText;
myText = getText("myTextInput");
write("Message #" + count + ": " + myText);
setText("myTextInput", "");
count = count + 1;
});
Syntax
x = ___;
Parameters
| Name | Type | Required? | Description |
|---|---|---|---|
| x | variable name | The name you will use in the program to reference the variable. Must begin with a letter, contain no spaces, and may contain letters, digits, - and _. | |
| ___ | any type | The right hand side of the assignment operator can be a number or a string, or the number or string returned by a function, or the numeric or string result of the evaluation of an expression. |
Returns
Tips
- The variable must be declared using var before it can be assigned its initial value.
- You can use the same variable on both the right hand side of the assignment operator = and the left hand side. This is sometimes used for a counter count = count + 1;
- = is the assignment operator. == is the boolean check for equivalency operator.
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