For (int num : array ) Here int is data type for num variable where you want to store all arrays data in otherwords you can say the destination where you want to give all component of arrays. Here array is the name of the array itself. So all arrays components we are giving to num variable. Even sum subsequence means the subsequence whose total sum( sum of all the elements in the subsequence) is divisible by 2. And for odd sum subsequence, the total sum leaves a remainder of 1 when divided by 2. Note: 1) In general, for an array of size 'N', there are (2 ^ 'N' - 1) non-empty subsequences possible. n = int (input ("Enter the size of the array: ")) print ("Enter the Element of the array:") for i in range (0,n): num = int (input ()) arr.append (num) print ("Sum of even Element is:",SumOfEvenElement (arr,n)) Input/Output: Enter the size of the array: 3. Enter the Element of the array:.