1、请使用递归实现n!

#include<stdio.h>
#include<string.h>	
#include<stdlib.h>int fun(int m)
{if(m==0)return 1;else{return m*fun(m-1);}
}
int main(int argc, const char *argv[])
{int m;printf("please enter m:");scanf("%d",&m);int sum=fun(m);printf("sum=%d\n",sum);return 0;
}

2、请使用递归实现O-n的和

#include<stdio.h>
#include<string.h>	
#include<stdlib.h>int fun(int m)
{if(m==0)return 0;else{return m+fun(m-1);}
}
int main(int argc, const char *argv[])
{int m;printf("please enter m:");scanf("%d",&m);int sum=fun(m);printf("sum=%d\n",sum);return 0;
}

3、请使用递归实现斐波那契

#include<stdio.h>
#include<string.h>	
#include<stdlib.h>
//斐波那契:任意三项 中间项的平方等于 前一项×后一项 减 1
int fun(int n)
{if(n<=2)return 1;else{return fun(n-1)+fun(n-2);}
}
int main(int argc, const char *argv[])
{int n=0;scanf("%d",&n);printf("第%d个:%d",n,fun(n));puts("");return 0;
}

4、请使用递归实现二进制转换

#include<stdio.h>
#include<string.h>	
#include<stdlib.h>
int fun(int m)
{if(m<2)return m;else{return m%2+fun(m/2)*10;}
}
int main(int argc, const char *argv[])
{int m;printf("please enter m:");scanf("%d",&m);int sum=fun(m);printf("二进制=%d\n",sum);return 0;
}

5、请递归实现计算各个位数字之和

#include<stdio.h>
#include<string.h>	
#include<stdlib.h>int fun(int m)
{if(m==0)return 0;else{return m%10+fun(m/10);}
}
int main(int argc, const char *argv[])
{int m;printf("please enter m:");scanf("%d",&m);int sum=fun(m);printf("sum=%d\n",sum);return 0;
}

6、请递归实现计算各个位数字的乘积

#include<stdio.h>
#include<string.h>	
#include<stdlib.h>int fun(int m)
{if(m==0)return 1;else{return m%10*fun(m/10);}
}
int main(int argc, const char *argv[])
{int m;printf("please enter m:");scanf("%d",&m);int sum=fun(m);printf("sum=%d\n",sum);return 0;
}

7、请使用递归实现计算单词逆置

#include<stdio.h>
#include<string.h>	
#include<stdlib.h>
void fun(char *p,int i,int j)
{char t;if(i==j)return;else{t=*(p+i);*(p+i)=*(p+j);*(p+j)=t;return fun(p,i+1,j-1);}
}
int main(int argc, const char *argv[])
{char str[20];printf("please enter str:");gets(str);int len=strlen(str)-1;fun(str,0,len);puts(str);return 0;
}