Line 1 to 3: import our useful libraries.
Line 5: determine how many elements should be select from your vector.
Line 6: determine the length of your vector.
Line 7 to 8: determine minimum and maximum bound of your random values.
Line 10: make a vector 
Line 12: make random values, that you decided bound and number of them in previous steps.
Line 14 to 15: round your random values to 2 digits.
Line 17 to 20: in this loop you check summation of your random values. if it is less than 1,you must add to the last value, the amount of difference between 1 and vectore's summation. else, you must minus to the last value, the amount of difference between 1 and vectore's summation.
Line 22: from your original vector, you decide some indexes that you decide number of them in 'Line 5'
Line 24 to 25: for indexes that selected in previous step, you assign their values.