Recursive exercises, recursion

Recursive exercises, recursion

Number Accumulation

Accumulate prime numbers

Sample Code:

# Include <iostream> int sum (int); int judge (int); int sumOfPlain (int); int main (int argc, char ** argv) {// printf ("% d \ n", sum (3); // printf ("% d \ n", judge (5 )); printf ("% d \ n", sumOfPlain (10); // 2 3 5 7 return 0;} int sum (int a) {if (a <= 0) {return 0;} else if (a = 1) {return 1;} else return a + sum (A-1);}/** determine whether it is a prime number, if yes, otherwise, 0 */int judge (int a) is returned. {// There are three methods: until the A-1 // verified is to a/2 but because there is not half of this situation, so we may wish to add one more Number of children // then there is the range of division to the beginning. If it is still not available, it will not be available. For (int I = 2; I <a/2 + 1; I ++) {if (a % I = 0) {return 0 ;}} return ;} int sumOfPlain (int a) {int afterJ = judge (a); if (a <= 1) {return 0;} else if (a = 2) {return 2 ;} else {return afterJ + sumOfPlain (A-1 );}}

Recursion:

Advantages of recursion: the simplest algorithms are provided for some problems: Tower of Hanoi, binary search, fast sorting, and Fibonacci series. Disadvantages: (if there is no proper exit) the computer's resources will soon be exhausted. recursive Programs are hard to understand and maintain. For windows, the screen will not respond, but for linux, the system will restart. The Linux kernel is written in this way. It is automatically restarted when there is no available space in its memory. Suddenly thought of a cell phone... Automatic Restart is because the memory is gone and the linux kernel is packaged... Many android viruses use a recursion to restart the mobile phone and install it.