实现常用字符串处理函数的功能，希望能交流看系统到底是怎么实现的-Implement the function of usuall string

Write an EXE program that accepts a string from the keyboard, converts it to HEX (this algorithm should also check to see if the input is a number), and stores it. It should take a second string and convert it to HEX, then add the two numbers,