include <stdio.h>

int zs = 0;
void wanmei (char s1[],int n);
int main ()
{
char s1[50]="x",s2[50]="y";
wanmei(s1,1);
wanmei (s2,1);
printf ("%d",zs);
return 0;
}
void wanmei (char s1[],int n)
{
int i,m,k;
if (n>=2&&s1[n-1]=='x'&&s1[n-2]=='x')
return;
if (n==30)
{
zs++;
return;
}
s1[n]='x';
wanmei (s1,n+1);
s1[n]='y';
wanmei (s1,n+1);
}
递归方法，大一新生C语言备考中~应该还能更简单