递归的基本概念与递归程序设计以及常见的递归算法

#include <stdio.h>

// 1. 求n!
int fact(int n)
{
    if(n <= 1)
        return 1;
    return n * fact(n-1);
}

// 2.Fibonacci数列，前两项为1，第三项开始每项等于前两项的和
int fibonacci(int n)
{
    if(n == 1 || n == 2)
        return 1;
    return fibonacci(n-1) + fibonacci(n-2);
}

// 3.打印数字三角形
void print(int n)
{
    if(n > 0)
    {
        print(n-1);
        for (int i = 1; i <= n; ++i)
            printf("%d ",n);
        printf("\n");
    }
}

// 4. 递归求数组的最大值
int max(int a[], int left, int right)
{
    int lMax, rMax, mid;
    if(left == right)
        return a[left];
    else
    {
        mid = (left+right)/2;
        lMax = max(a,left,mid);
        rMax = max(a,mid+1,right);
        return lMax > rMax ? lMax : rMax;
    }
}

int main()
{
    int n = 5;
    printf("%d! = %d\n",n,fact(n));
    printf("fibonacci数列的第%d项为%d\n",n,fibonacci(n));
    print(5);
    int a[10] = {1,2,3,4,5,11,7,8,9,10};
    printf("数组最大的数是：%d", max(a,0,9));
    return 0;
}