hello people. How do I compute the difference in dates of the same year without using datenum or any other built in function

I need to compute the difference in days between any two dates of the same year.How do I go about it, without using built in functions in matlab

[the cyclist]

Is this homework? It seems like homework. What have you tried. Maybe we can give you some hints.

[Image Analyst]

Why can't you use built-in functions? Why make it hard on yourself?

Try this http://www.mathworks.com/matlabcentral/answers/38787-what-can-be-programmed-without-any-built-in-functions

http://www.mathworks.com/matlabcentral/answers/8626-how-do-i-get-help-on-homework-questions-on-matlab-answers

[Jan]

You can't do anything useful without using built-in commands in Matlab.

In which format are the dates available? You could start Excel from Matlab and perfomr the calculations there. Would this solve the yout question?