该题目为第一章第八题。

# 要求输入文件名
fileName = input("Enter file name:")

#打开文件
inputFile = open(fileName, 'r')
lines = list()
for line in inputFile:
    lines.append(line)

while True:
    print("The file has", len(lines), "lines.")
    if len(lines) == 0:
        break
    lineNumber = int(input("Enter a line number: "))
    if lineNumber == 0:
        break
    elif lineNumber >= len(lines):
        print("ERROR")
    else:
        print(lineNumber, ": ", lines[lineNumber])