（递归/非递归）斐波那契数列

#include<stdio.h>

int Fib(int x) {
  if (x <= 2) {
    return 1;
  }
  else {
    return Fib(x - 1)+Fib(x-2);
  }
}
//效率很低
int fib(int x) {
  int i = 1;
  int a = 1;
  int b = 1;
  while (x > 2) {
      i = a + b;
    b = a;
    a = i;
    x--;
  }
  return i;
}
//效率很高
int main() {
  int num = 0;
  printf("请输入想要查询的第几位数字：");
  scanf_s("%d", &num);
  printf("%d\n", Fib(num));
  printf("%d", fib(num));
  return 0;
}