Variables Kevin Harville Variables Variables are a named

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Variables Kevin Harville

Variables Kevin Harville

Variables ® Variables are a named space in the computer where a value is

Variables ® Variables are a named space in the computer where a value is stored. ® Examples ® User’s age ® User’s name ® Any characters or numbers you need use in which the values may vary.

Variable Names ® Names are CASE SENSITIVE ® Var total. Students is not Total.

Variable Names ® Names are CASE SENSITIVE ® Var total. Students is not Total. Students ® Use letters or underscore. Can use numbers after the first character var Student_Name; ® var Score 7; ® ® Be descriptive. Use no punctuation or spaces. ® var Number. Of. Fish. In. Grandmas. Aquarium;

Variable Scope ® The “scope” of a variable is the range within the program

Variable Scope ® The “scope” of a variable is the range within the program where it can be used. ® If a variable is declared within a function, the scope of the variable is local, meaning limited to that function. ® Other variables are global to the entire script.

Data Types ® Variables in Java. Script are variant. That means that they are

Data Types ® Variables in Java. Script are variant. That means that they are usually not specified as being a particular type of data, such as characters, a decimal number, or a number. ® However, we can specify our data as being of a particular type if needed.

Data Types ® Numbers ® Boolean ( true / false ) ® Strings (characters)

Data Types ® Numbers ® Boolean ( true / false ) ® Strings (characters) ® Null values (Java. Script keyword null)

Converting Strings to Numbers ® Any input from the user may be considered by

Converting Strings to Numbers ® Any input from the user may be considered by the computer to be strings of characters. ® “ 10” + “ 40” = “ 1040” ® Therefore we tell the computer to consider the text to be integer or floating point (decimal numbers). ® age = parse. Int(age); ® my. Fraction = parse. Float(my. Input);

Just Remember… ® If your input should be an integer convert it using parse.

Just Remember… ® If your input should be an integer convert it using parse. Int(). ® If your input should be a decimal convert it using parse. Float(). ® If your response is Na. N, then the computer can’t convert it to a number