题解 | #进制转换#

dec_num = 0

while 1:
    try:
        hex_num = input().lower()
        if not hex_num: break
        if '0x' in hex_num:
            hex_num = hex_num[2:]
        MSB = len(hex_num)
        for i in range(MSB):
            hex_char = hex_num[i]
            if hex_char == 'f':
                dec_num += 15 * 16**(MSB - 1 - i)
            elif hex_char == 'e':
                dec_num += 14 * 16**(MSB - 1 - i)
            elif hex_char == 'd':
                dec_num += 13 * 16**(MSB - 1 - i)
            elif hex_char == 'c':
                dec_num += 12 * 16**(MSB - 1 - i)
            elif hex_char == 'b':
                dec_num += 11 * 16**(MSB - 1 - i)
            elif hex_char == 'a':
                dec_num += 10 * 16**(MSB - 1 - i)
            else:
                dec_num += int(hex_char) * 16**(MSB - 1 - i)
        print(dec_num)
    except:
        break

1. 穷举法进制转换
2. try-except语句用来判定是否接收到了新的输入