Variables Kevin Harville Variables Variables are a named
Variables Kevin Harville
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. 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 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 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) ® Null values (Java. Script keyword null)
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. 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
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