Question

why main function is used as a user defined but not as pre-defined?

Answer 1

The main function in java AKA " public static void main(String[]args)" is known as user defined type because we write 'String[]args' inside the round brackets .but if you have a program for accepting the value to a variable in the main method by the call dialog box which appears before the output window,we write the main method as 'public static void main(int a)"hence the variable and the data type inside the round brackets are defined by the user .. so its a user defined function