《Python编程：从入门到实践》习题答案——第10章 文件和异常

# 10-1 Python学习笔记

# 10-6 加法运算：
print("Give me two numbers, and I'll add them.")
try:
    num1 = input("num1: ")
    x = int(num1)

    num2 = input("num2: ")
    y = int(num2)

except ValueError:
    print("您输入的不是数字！")

else:
    print(x + y)

# 10-7 加法计算器
print("Give me two numbers, and I'll add them.")
print("Enter 'q' to quit.")

while True:
    try:
        num1 = input("First number: ")
        if num1 == 'q':
            break
        x = int(num1)

        num2 = input("Second number:")
        if num2 == 'q':
            break
        y = int(num2)
    except ValueError:
        print("您输入的不是数字！")
    else:
        print(x + y)

# 10-8 猫和狗
def print_txt(filename):
    """打印文件中内容"""
    try:
        with open(filename) as f:
            contents = f.read()
    except FileNotFoundError:
        print(f"{filename} ,This file does not exist.")
    else:
        print(contents)

filenames = ['cats.txt', 'dogs.txt']
for filename in filenames:
    print_txt(fi