Recursive note 1: application scenarios and call mechanism

1, the concept of recursion:

That calls itself recursively , each invocation, passing different variables, recursive help solve complex problems, while allowing code becomes simple .

2, the recursive call mechanism

Printing problems

com.ethjava Package; 

public class diguidayin { 
    public static void main (String [] args) { 
        Test (. 4); 
    } 
    public static void Test (n-int) { 
        IF (n-> 2) { 
            Test (. 1-n-); 
        } 
        System.out.println ( "Print n-:" n-+); 
    } 
} 
// Print n-: 2 
// Print n-:. 3 
// Print n: 4

Recursive call rules:

1) When the program executes a method, it will open up a separate space: Stack

2) data of each space (local variables) are independent and do not affect each other

2) is as follows:

 

Recursion to solve the problem:

1. algorithms: merge sort, quick sort, binary search

2, mathematical problem: the Towers of Hanoi problem, factorial problem, 8 Queen

3, to solve the problem with a stack of: recursively resolve will be very simple.

 

Recursive need to comply with the principles of:

1) the implementation of a method, it creates a new protected independent space.

2) data for each process (local variables) are independent and do not affect each other

3) If the variable is a reference type (such as arrays) used in the method, reference will be shared by the type of data stored in the heap.

4）递归必须向退出递归的条件逼近，否则就是无线递归，出现StackOverflowError,

5) 当一个方法执行完毕后，或者遇到return，就会返回到调用的位置，继续往下执行。

遵守规则：谁调用，就将结果返回给谁，同时当方法执行完毕或者返回时，该方法也就执行完毕。