Recursive function C language question type

Recursive function C Language Question type

1. subject ： Yes 5 A person sits together , Ask No 5 How old is an individual ？ He said bidi 4 Personal big 2 year . Ask No 4 Personal age , He said bidi 3 Personal big 2 year .
Ask No 3 personal , And he said bidi 2 People are two years old . Ask No 2 personal , Say bidi 1 I'm two years older . Last Ask No 1 personal , He says it is 10 year . May I ask 5 How old are you ？
Program analysis ： Using recursive methods , Recursion can be divided into two stages: backward and recursive . If you want to know the second 5 Personal age , Need to know the second 4 People's age , By analogy , Push it to the second 1 people （10 year ）, Push back .

#include <stdio.h> 
int age(a)//a For whom 
{
    
    int i;//i Used to store age 
    if(a==1)
    {
     
	    i=10;
    	return i;
	} 
    else
    {
    
		i=age(a-1)+2;
		printf(" The first %d The number of rounds is %d\n",a,i);
    	return i;
	} 
}
int main() 
{
    
    int Age=age(5);
	printf(" The first 5 An individual's age is %d year ", Age); 
	return 0;
}

2. subject ： Calculation 1+2+3+…+100

#include <stdio.h>
int func(int a)
{
    
	int b;
	if(a>0)
	{
    
		b=a+func(a-1);
	}
	return (b);
}
int main()
{
    
	int a=100,b;
	b=func(a);
	printf("1+2+3+...+100 The value of is %d",b);
}

3. Calculation 10 The factorial （ You can rewrite... Based on the previous question ）
Tips ： here 10 Don't change it again ,10 The factorial of is already a large number .

#include <stdio.h>
int func(int a)
{
    
	static unsigned long long int c;
	if(a==0)
	{
    
		return 1; 
	}	
	else
	{
    
		c=a*func(a-1);
	}
	return (c);
}
int main()
{
    
	int a=10;
	unsigned long long int b;
	b=func(a);
	printf("100！ The value of is %d",b);
}

4. Fibonacci sequence
   Fibonacci sequence is the third number, which is equal to the sum of the first two numbers .

#include <stdio.h>
int fibonaci(int i)
{
    
   if(i == 0)return 0;
   if(i == 1)return 1;
   return fibonaci(i-1) + fibonaci(i-2);
}
int  main()
{
    
    int i;
    for (i = 0; i < 10; i++)
    {
    
       printf("%d\t\n", fibonaci(i));
    }
    return 0;
}