"how come the setting of a port as input and making a port high have the same codes? then how do I differentiate between the two?"

This question has been answered many, many times on this forum. Why don't you try searching for the answer?

As you seem to be using the 8051 for your final year project, don't you think you should get yourself a manual which explains how the 8051 works? Hint: manuals are available for download on this website.