"How can i open the attached text file..."
Download the file, then run either:
V = readmatrix('Xc.txt');
"..or other formate file given in community in my own matlab"
That depends entirely on the file format: if it is a standard file format then you can probably use one of the inbuilt file importing functions:
otherwise you might have to find some third-party function that supports a particular file format, or write your own file importing function based on the specification of that file format.