第47课 递归函数分析

 1 #include <stdio.h>
 2 
 3 int strlen_r(const char* s)
 4 {
 5     if( *s )
 6     {
 7         return 1 + strlen_r(s+1);
 8     }
 9     else
10     {
11         return 0;
12     }
13 }
14 
15 int main()
16 {
17     printf("%d\n", strlen_r("abc"));
18     printf("%d\n", strlen_r(""));
19     
20     return 0;
21 }

 1 #include <stdio.h>
 2 
 3 int fac(int n)
 4 {
 5     if( n == 1 )
 6     {
 7         return 1;
 8     }
 9     else if( n == 2 )
10     {
11         return 1;
12     }
13     else
14     {
15         return fac(n-1) + fac(n-2);
16     }
17     
18     return -1;
19 }
20 
21 int main()
22 {
23     printf("%d\n", fac(1));
24     printf("%d\n", fac(2));
25     printf("%d\n", fac(9));
26     
27     return 0;
28 }

 1 #include <stdio.h>
 2 
 3 void han_move(int n, char a, char b, char c)
 4 {
 5     if( n == 1 )
 6     {
 7         printf("%c --> %c\n", a, c);
 8     }
 9     else
10     {
11         han_move(n-1, a, c, b);
12         han_move(1, a, b, c);
13         han_move(n-1, b, a, c);
14     }
15 }
16 
17 int main()
18 {
19     han_move(3, ‘A‘, ‘B‘, ‘C‘);
20     
21     return 0;
22 }