C语言之函数递归的实现

//例子：
void func()
{
	//...
	if(...)
		func();//调用自身
	else
	//...
}

#include<stdio.h>
int main()
{
	int n=123;
	int a = n / 100;//取百位
	int b = (n / 10)%10;//取十位
	int c = n % 10;//取个位
	//依次输出
	printf("%d %d %d\n", a, b, c);
	return 0;
}

#include<stdio.h>
void Fun_c(int x)
{
	if (x >9)//限制条件
	{
	Fun_c(x/10);
	}
	printf("%d ", x%10);
}
int main()
{
	int n;
	scanf("%d", &n);
	Fun_c(n);
	return 0;
}

int Length(char* s)
{
	if (*s == '\0')//限制条件
		return 0;
	else
		return 1 + Length(s + 1);
}
#include<stdio.h>
int main()
{
	char* ch = "iloveC";//字符串结束标志:'\0'
	int len = Length(ch);
	printf("%d", len);
	return 0;
}

//递归
#include<stdio.h>
int Fac(int n)
{
	if (n == 1)//限制条件
		return 1;
	else
		return n * Fac(n - 1);
}
int main()
{
	int n;
	scanf("%d", &n);
	int temp = Fac(n);
	printf("%d\n", temp);
	return 0;
}

//迭代
int Fac(int n)
{
	int temp = 1;
	for (int i = 1; i <= n; i++)
	{
		temp = temp * i;
	}
	return temp;
}
#include<stdio.h>
int main()
{
	int n;
	scanf("%d", &n);
	printf("%d\n", Fac(n));
	return 0;
}

//递归
#include<stdio.h>
int Fib(int n)
{
	if (n == 1 || n == 2)//限制条件
		return 1;
	else
		return Fib(n - 1) + Fib(n - 2);
}
int main()
{
	int n;
	scanf("%d", &n);
	printf("%d\n", Fib(n));
	return 0;
}

//迭代
#include<stdio.h>
int Fib(int n)
{
	int a = 1;
	int b = 1;
	int c;
	while (n >= 3)
	{
		c = a + b;
		a = b;
		b = c;
		n--;
	}
	return c;
}
int main()
{
	int n;
	scanf("%d", &n);
	printf("%d\n", Fib(n));
	return 0;
}