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A variable is a placeholder for a value. Variables Variables are used for storing values. In Java, variables need to be defined with a data-type, to define its storage space requirements. The name of the variable must start with a letter, but it may contain numbers within the name. In processing, variable names are case-sensitive.

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// variable Declaration 
int x1 = 15; // an integer i.e a whole number 
float valF = 0.323; // a floating point number i.e a numbers with a decimal point
boolean bFlag = false; // a true or false value i.e a single bit value
String message = "hallo 1"; // a collection of characters 
char character = 'g'; // a siglesingle character. Note the different quotation marks
 
String msg1 = new String("hallo 2");
 
println(x1);
println(valF);
println(bFlag);
println(message);
println(character);
println(msg1);

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Each kind of variable (it's data type) has an allocated amount of memory, which is enough to store a particular range of values. 

Operators 

An operator is a symbol that tells the computer to perform a particular math or logic operation. Some of the most common operators are:

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