栈帧l练习

//1:递归求第n个斐波那契数
/*#include<stdio.h  >
#include<windows.h>
int fib(int n)
{
	if (n < 3)
	{
		return 1;
	}
	else return fib(n - 1) + fib(n - 2);
}
int main()
{
	int n = 3;
	int ret=fib(n);
	printf("%d", ret);
	system("pause");
	return 0;
}*/
//1:迭代求第n个斐波那契数
/*#include<stdio.h>
#include<windows.h>
int fib(int n)
{
	int first = 1;
	int second = 1;
	int third = 0;
	while (n <= 2)
	{
		return 1;
	}
	while (n > 2)
	{
		n--;
		third = first + second;
		first = second;
		second = third;
	}
	return third;
}
int main()
{
	int n = 5;
	printf("%d\n", fib(n));
	system("pause");
	return 0;
}*/
//2:n^k递归法
/*#include<stdio.h>
#include<windows.h>
int fun(int n ,int k)
{
	if (k == 0)
	{
		return 1;
	}
	else {
		return n*fun(n, k - 1);
	}
}
int main()
{
	int n=2;
	int k = 5;
	int ret = fun(n,k);
		printf("%d\n", ret);
	system("pause");
	return 0;
}*/
//3: 写一个递归函数DigitSum(n)，输入一个非负整数，返回组成它的数字之和，例如，调用DigitSum(1729)，则应该返回1+7+2+9，它的和是19 
/*#include<stdio.h>
#include<windows.h>
int DigitSum(int n)
{
	int add = 0;
	if (n > 9)
	{
		add=DigitSum(n / 10);
	}
	return n % 10+add;
	
}
int main()
{
	int n = 1728;
	int add =DigitSum(n);
	printf("%d\n", add);
	system("pause");
	return 0;
}*/
//4:编写一个函数reverse_string(char * string)（递归实现）
/*#include<stdio.h>
#include<windows.h>
char* reverse_string(char * string)//一维数组传参时，降为一级指针
{
	int n = 0;
	char *tring;
	char temp;
	tring = string;//将原始的字符串保存到string指针中
	while (*string != 0)//求得字符串长度n,让string指针指向最后一个数组元素的地址
	{
		n++;
		string++;
	}
	if (n > 1)
	{
		temp = tring[0];//将第一个元素给中间变量
		tring[0]=tring[n-1];//将最后一个元素给第一个元素
		tring[n - 1] = '\0';//最后一个位置放\0
		reverse_string(tring + 1);//使用递归法，重复上面的操作
		tring[n-1] = temp;
	}
	return tring;
}
int main()
{
	char string[] = "abcdefg";
	printf("翻转前：%s", string);
	printf("\n");
	printf("翻转后：%s",reverse_string(string));
	system("pause");
	return 0;
}*/
//5:递归实现strlen
/*#include<stdio.h>
#include<windows.h>
int strlen(const char*str)
{
	if (*str == '\0')
	{
		return 0;
	}
	else return 1 + strlen(str + 1);
}
int main()
{
	char*p = "abcdefg";
	int len = strlen(p);
	printf("%d\n", len);
	system("pause");
	return 0;
}*/
//5:非递归实现strlen
/*#include<stdio.h>
#include<windows.h>
int strlen(const char*str)
{
	int count = 0;
	while (*str ++)
	{
		count++;
	}
	return count;
}
int main()
{

	char*p = "abcdefg";
	int len = strlen(p);
	printf("%d\n", len);
	system("pause");
	return 0;
}*/
//6:递归和非递归分别实现求n的阶乘
/*#include<stdio.h>
#include<windows.h>
#define _CRT_SECURE_NO_WARNINGS 1 
int fun1(int n)
{
	if (n <= 1)
	{
		return 1;
	}
	else return n*fun1(n - 1);
}
int fun2(int n)
{
	int ret = 1;
	while (n > 1)
	{
		ret *= n;
		n--;
	}
	return ret;
}
int main()
{
	int n = 4;
	printf("%d\n", fun1(n));
	printf("%d\n", fun2(n));
	system("pause");
	return 0;

}*/
//7:递归方式实现打印一个整数的每一位 
/*#include<stdio.h>
#include<windows.h>
void fun(int num1)
{
	if (num1 >= 10)
	{
		fun(num1 / 10);
	}
	printf( "%d ",num1 % 10);
}
int main()
{
	int num = 123456;
	printf("%d\n", num);
	fun(num);
	system("pause");
	return 0;
}*/
//5：实现一个函数，可以左旋字符串中的k个字符。 
//ABCD左旋一个字符得到BCDA
//ABCD左旋两个字符得到CDAB
/*#include<stdio.h>
#include<windows.h>
void fun(char *p,int k,int size)
{
	k %= size;
	int i = 0;
	int j = 0;
	char temp ;
	for (i=0; i < k; i++)
	{
		temp = p[0];
		for (j=0; j < size - 1; j++)
		{
			p[j] = p[j + 1];
		}
		p[size-1] = temp;
	}
}
int main()
{
	char a[] = "ABCD";
	int size = strlen(a);
	printf("旋转签的字符串：%s", a);
	int k;
	printf("请输入旋转k:");
	scanf_s("%d\n",&k);
	fun(a, k, size);
	printf("%s", a);
	system("pause");
	return 0;
}*/
//6:判断一个字符串是否为另外一个字符串旋转之后的字符串。 
//例如：给定s1 ＝ AABCD和s2 = BCDAA，返回1，给定s1 = abcd和s2 = ACBD，返回0.
#include<stdio.h>
#include<windows.h>
#include<string.h>
int fun_s(char*a,char*b,int size,int sz)
{
int i = 0;
int j = 0;
int temp = 0;
int count = 0;
for (; i < size; i++)
{
	for (j = i; j < sz; j++)
	{
		if (a[i] != b[j])
		{
			count ++;
		}
	}
}
}
void fun(char *p, int k, int size)
{
	k %= size;
	int i = 0;
	int j = 0;
	char temp;
	for (i=0; i < k; i++)
	{
		temp = p[0];
		for (j=0; j < size - 1; j++)
		{
			p[j] = p[j + 1];
		}
		p[size-1] = temp;
	}
}
int main()
{
	char a[] = "ABCD";
	char b[] = "CDAB";
	int size = strlen(a);
	int sz = strlen(b);
	printf("旋转签的字符串：%s", a);
	int k;
	printf("请输入旋转k:");
	scanf_s("%d\n", &k);
	fun(a, k, size);
	printf("%s", a);
	printf("\n");
	int count=fun_s(a, b, size, sz);
	if (count == 1)
		printf(" 不相同%d", 0);
	else printf(" 相同%d", 1);
	system("pause");
	return 0;
}