函数定义

# 为什么需要函数
# 对重复的代码进行封装
# def 函数名(参数...):
#     函数体
# 函数名(实参)
def sayHello():
    print("哈哈")
    print("哈哈")
# 调用函数
sayHello()
# 1~任意数的累加和
def caculateNum(number):
    sum = 0
    for i in range(1, number+1):
        sum += i
    print(sum)
caculateNum(2)
caculateNum(50)
caculateNum(100)
caculateNum(500)
# 任意两个数的相加
def sum_two(x, y):
    print("x =", x)
    print("y =", y)
    print(x + y)
sum_two(10, 20)
sum_two(-10, 20)

demo2

# + - x /
def jia(a, b):
    print(a + b)
def jian(a, b):
    print(a - b)
def mul(a, b):
    print(a*b)
def div(x, y):
    print(x/y)
num1 = input("请输入第一个数") # "1"
num1 = int(num1)
# print(type(num1))
fuhao = input("请输入运算符(+ - * /)")
num2 = int(input("请输入第二个数"))
if fuhao=="+":
    print("+")
    jia(num1, num2)
elif fuhao=="-":
    print("-")
    jian(num1, num2)
elif fuhao=="*":
    print("*")
    mul(num1, num2)
elif fuhao=="/":
    print("/")
    div(num1, num2)
else:
    print("输入有误")

demo2

# 函数的类型
# 无参无返回
def haha():
    print("哈哈")
# 有参无返回
haha()
def add(x, y):
    print(x+y)
# 有参有返回
print(add(10, 20))
def add2(x, y):
    return x + y
# res = add2(11, 22)
# print(res)
print(add2(30, 70))
# 无参有返回
def haha2():
    return "呵呵呵"
print(haha2())