7. a. Write a C program that stores the integer value 15 in the variable num1 and the inte- ger value 18 in the variable num2. (Make sure to declare these two variables as integers.) Have your program calculate the total of these numbers and their average. The total should be stored in the variable named total and the average in the vari- able named average. (Use the statement average = total/2.0; to calculate the average.) Use the printf() function to display the total and average. b. What data type did you have to declare for the average to ensure that the correct answer was calculated and displayed?