输入一段字符,将字符串里面的标点符号替换成空格,采用字典数据结构统计词语出现频率,输出文章中最常出现的 6 个单词记出现次数。 程序运行示例为: 请输入一个字符串: IT WAS the best of times, it was the worst of times, it was theage of wisdom, it was the age of foolishness, it was the epoch of belief, it was the epoch of incredulity. it 6 was 6 of 6 the 5 times 2 epoch 2