递归和非递归分别实现求第n个斐波那契数。
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//(1)递归的方法:
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
int Fib(int n)
{
if (n == 1 || n == 2)
{
return 1;
}
return Fib(n - 1) + Fib(n - 2);
}
int main()
{
int n = 0;
printf("please input a num:");
scanf("%d", &n);
int num = Fib(n);
printf("%d\n", num);
system("pause");
return 0;
}
//(2)非递归的方法:(循环)
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
int Fib(int n)
{
if (n == 1 || n == 2)
{
return 1;
}
int num1 = 1;
int num2 = 1;
int sum = 0;
for (int i = 3; i <= n; ++i)
{
sum = num1 + num2;
num1 = num2;
num2 = sum;
}
return sum;
}
int main()
{
int n = 0;
printf("请输入要求的斐波那契数列的项数:\n");
scanf("%d", &n);
int num = Fib(n);
printf("%d\n", num);
system("pause");
return 0;
}
编写一个函数实现n^k,
//(1)非递归实现:(n为整数,不考虑k为分数,负数)
#define _crt_secure_no_warnings
#include<stdio.h>
#include<stdlib.h>
int factor(int n,int k)
{
int mul = 1;
for (int i = 1; i <= k; ++i)
{
mul = mul*n;
}
return mul;
}
int main()
{
int n = 0;
int k = 0;
printf("请输入n和k:");
scanf("%d %d", &n,&k);
int num = factor(n,k);
printf("%d\n", num);
system("pause");
return 0;
}
////(2)递归实现
#define _CRT_SECURE_NO_WARNINGS//(n为整数,不考虑k为分数,负数)
#include<stdio.h>
#include<stdlib.h>
int Factor(int n, int k)
{
if (k == 1)
{
return n*1;
}
else
{
return Factor(n, k-1)*n;
}
return 0;
}
int main()
{
int n = 0;
int k = 0;
printf("请输入n和k:\n");
scanf("%d %d", &n, &k);
int num = Factor(n, k);
printf("%d\n", num);
system("pause");
return 0;
}
递归方式实现打印一个整数的每一位
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
void Factor(int n)
{
int tmp = 0;
if (n > 9)
{
Factor(n / 10);
}
printf("%d\n", n % 10);
}
int main()
{
int n = 0;
printf("请输入一个数字:\n");
scanf("%d", &n);
Factor(n);
system("pause");
return 0;
}
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
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
int DigitSum(int n)
{
if (n > 0)
{
return n % 10 + DigitSum(n / 10);
}
return 0;
}
int main()
{
int num = 0;
scanf("%d", &num);
printf("%d\n", DigitSum(num));
system("pause");
return 0;
}
递归和非递归分别实现求n的阶乘
//(递归方法:)
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
int Fac(int num)
{
if (num == 1)
{
return 1;
}
if (num > 1)
{
return Fac(num - 1)*num;
}
return 0;
}
int main()
{
int n = 0;
scanf("%d", &n);
int num = Fac(n);
printf("%d\n", num);
system("pause");
return 0;
}
(1)非递归方法:
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
int main()
{
int n = 0;
scanf("%d", &n);
int mul = 1;
for (int i = n; i > 0; --i)
{
mul *= i;
}
printf("%d\n", mul);
system("pause");
return 0;
}