编写函数catstr(char str1[],char str2[])用于进行两个字符串的连接，编写函数lenstr(char str[])用于统计一个字符串的长度，并在主函数中调用。要求：1.不允许使用strcat（）和strlen（）字符处理库函数。2.在主函数中，以直接初始化的方式输入两个字符串。调用函数lenstr（）计算并返回两个字符串的长度。3.调用函数lenstr()计算并返回连接后的字符串的长度。并输出。-Write function catstr (char str1 [], char str2 []) for the connection of two strings, to write function lenstr (char str []) for statistical length of a string, and call in the main function. Requirements: 1. Not allowed to use the strcat () and strlen () character handling library functions. 2 in the main function to direct initialized input two strings. Call the lenstr () function calculates and returns the length of the two strings. Call the function lenstr () calculates and returns the concatenated string length. And output.