Variables and Data Types
To create a variable you first need a name. A variable name must start with a letter or underscore and then be followed by any combination of letters, underscores or digits as long as the name in the end isn't a reserved word like "int". Secondly you need a type which defines how the data is stored in memory for example int is an integer. When writing int x; you are declaring a variable which reserves the space in memory to hold the later on assigned value as it knows the amount of bytes the data type of the variable needs. Initializing a variable is giving it an initial value. This can be done as part of the declaration like for example int a = 12;.