Fibonacci sequence，求斐波那契數列

Fibonacci sequence，求斐波那契數列——迭代

def function_1(n):
    n1 = 1
    n2 = 1
    n3 = 1
    if n < 1:
        print("輸入有誤,輸入值要求大於等於1")
        return -1
    while(n - 2 > 0):
        n3 = n2 + n1
        n1 = n2
        n2 = n3
        n -= 1
    return n3
    
x = int(input("輸入一個正整數:"))
result = function_1(x)
print(result)     

Fibonacci sequence，求斐波那契數列——遞歸

def function_2(n):
    if n < 1:
        print("輸入有誤,輸入值要求大於等於1")
        return -1
    
    if n==1 or n ==2:
        return 1
    
    else:
        return function_2(n-1) + function_2(n-2)
    
x = int(input("輸入一個正整數:"))
result = function_2(x)
print(result)