options for if else condition

Hello sir, I have to use five slots but if two slots out of these five are free then as per users instruction randomly any one of these should be filled .

currently i am using it like as

 if(c1 < 10)
            s1 = ------------------

    elseif (c2 < 80)
            s2 = ------------------

        elseif(c3 < 8)
            s3 = ------------------    

        elseif(c4 < 8)
            s4 = ------------------

        elseif(c < 8)
            s5 = ----------;

        end

please suggest me any other conditional statement so that i can select any one of the slot randomly.

[Walter Roberson]

What are the c* values? Are you trying to designate probabilities of selection? I notice that they do not add up to 100.