Fibonacci numbers is a sequence of numbers, where each number (except the first two) is the sum of the two preceding numbers. The first two Fibonacci numbers are 0 and 1.
0, 1, 1, 2, 3, 5, 8, 13, 21, …
Write a program to input a number n (>= 0), and print the nth Fibonacci number (starting from the 0th number.)
Tip: You may establish a loop and compute two consecutive Fibonacci numbers in each iteration. Also, Fibonacci numbers can be very large, use variables of type long long to hold them.

#include<stdio.h>

int www(int i);

int main(){
int n,result;

printf("Enter a Num:");
scanf("%d",&n);

result = www(n);
printf("The Answer is:%d\n",result);

return 0;
}

int www(int i)
{
if( i== 0 || i == 1)
return i;
else return (www(i-2)+www(i-1));
}

把上面所有的int改问long就可以了

那www是什么意思?可以改成另外的么?新手我,多指教下,谢谢啦

自定义的一个函数名,这个你喜欢怎么定义都行,只要不和系统定义的函数名相同即可.(不加该函数头文件的除外)

Fibonacci数列本身就是一个递归解释.
F(n)=F(n-1)+F(n-2);
F(1)=1,F(2)=1;

long Fibonacci(int n)
{
if(n==1||n==2)return 1;
return(Fibonacci(n-1)+Fibonacci(n-2));
}

非递归解法
a=1,b=1;
for(i=1;i<n;i++)
{
t=a+b;
a=b;
b=t;
}
Print(b);