can someone help me

*Create a C program that will use the application of function in the program. The program will not accept 0 and above 20 as the number of inputs, the program will display "Invalid Input" when encounter these numbers. The program will ask again for a valid number of inputs.
Sample I/O:
Enter number of inputs: 3
Num1: 1
Num2: 2
Num3: 4
Sum is 7 and the product is 8
Highest value is 4 and the lowest value is 1
Repeat the process? [Press 1 for yes, other #s for exit]
Note: You are asked to create a function prototypes and definitions for computing the sum, computing the product, finding the highest, and finding the lowest. The inputs should be done using a repetition statement