编写函数int index返回字符t在字条串s中出现的最左边的位置，如果在s中没有与t匹配的子串，不返回-1-function int index prepared to return to the characters not string's note appeared in the leftmost position, If s and t is not matched substring, not to return -1

保护模式下编程。通过陷阱门INT 0FEh进行字符串输出。通过任务状态段TSS进行任务切换 -Protected mode programming. INT 0FEh through the trap door to the output string. Through the Task State Segment TSS for task switching

对中断的调用。对文件写字符串。共五个例程。test66 是在显示屏上出现彩色字符串。-using int。 write string to an archive。

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,