1. 编写程序完成截取字符串s中从第m个位置开始的n个字符，返回所截字符串的首地址，理解指针与字符数组的关系。

2.一行文字，找出其中大写字每、小字字母、数字及其它字符各有多少。-1. Preparation process is complete interception of the string s from the beginning of the first m positions of the n characters, the return of the cut-off the first string address pointer with the understanding of the relationship between character array. 2. A line of text to identify each of them write, in small letters, numbers and other characters in the respective numbers.