simle code of C# for .peek .copyto and .cloe is needed

i have five buttons (push , pop , peek , copyto , and cloe) and a list box on a form. shen i click push buuton it pushes data on stack and disply in listbox . when i press pop one element is removed from stack and display one less data from previous . now shat is the simpal practical code for peek , copyto and clone buttons to take some action
please some body heip me . but some quickly. it is my assingment on monday.
thakns