C # language basics-recursion,

C # language basics-recursion,

Recursion

1. Concept conception:

The function itself is called in the body until it meets a certain condition and does not continue to be called.

2. conditions should be met. factor:

(1) There is a process of repeated execution (calling itself );

(2) Conditions for jumping out of the repeated execution process (function Exit)

Iii. example

Factorial calculation n! = N * (n-1) * (n-2) * (n-3 )*...... * 1 (n> 0)

// Int sum = I * jiecheng (I-1); parse

// I = 5

// Int sum = 5 * jiecheng (4 );

// Int sum = 5*(4 * jiecheng (3 ));

// Int sum = 5*(4*(3 * jiecheng (2 )));

// Int sum = 5*(4*(3*(2 * jiecheng (1 ))));

// Int sum = 5*(4*(3*(2*1 )));

Iv. Notes notice:

1. A condition for loop end must exist in recursion.

2. Each call to a recursive function requires stack storage. If the number of calls is too large, Stack Overflow may occur.

 

Example: 1. A group of sheep rushed to each village for sale. Every time a village was lost, the total number of 1/2 and 1 were lost. After 7 villages, there were two left. Then, I asked how many sheep were first evicted.

 

2. Write recursive functions for 2*4*6 *...... * (2n) Result

 

3. There is a pair of female and female rabbits. Every month, they can breed a pair of rabbits. How many rabbits are there after n months?