用C语言实现的打印字符串中的子串的程序，输入一个字符串，输入起始位置和要打印子串的长度，将其打印出来，如果起始位置超出字符串范围或者子串长度超出字符串范围，则会报错。-Using C language print string substring procedures, enter a string, enter the starting location and want to print the length of substring to print it, if the start position beyond the scope of string or substring is longer than the string scope, it will error.