Int stands for a class and is an integer class. In other words, you have to follow an integer. If it is a decimal, it will be reported as an incompatible type. The range of int values is very large,

Is: [-(3 1 to the second power)] to [+(3 1 to the second power)-1],

It is enough to have int at ordinary times, and others such as short and lang are rare, because they are object-oriented, that is, they should be related to objective reality. Lang is generally only used for astronomical figures.