1写一个函数，求一个字符串的长度，在main函数中输入字符串，并输出其长度。　

2有n个人围成一圈，顺序排号。从第一个人开始报数（从1到3报数），凡报到3的人退出圈子，问最后留下的是原来第几号的那位。

3编写input()和output()函数输入，输出5个学生的数据记录。

4反向输出一个链表。

5找到年龄最大的人，并输出。-1 to write a function, and the length of a string, in the main function in the input string and output its length. 2 There are n individuals form a circle, in that order排号. From the first person to start off (from the reported number of 1-3), who reported 3 people out of the circle and asked the last remaining original issue of who the first few. 3 preparation of input () and output () function input and output data of the five student records. 4 reverse a linked list output. 5 to find the oldest, and output.