How do I write these functions?

11. Write a function to calculate the sum of the values stored in an array. Use the following prototype to make the exercise easier. float sumArray(float arr[l, int size); 14. Write a function to compute the average of an unspecified number of grades. The loop should stop on the input of a negative value. Extra credit will be given if it also gracefully handles when a string is entered 15. Tammy has written the following lines of code to collect names until she enters a "q' or Q: instead of stopping it treats 'q' and 'O as really short names. Why? char val[50] do t printf("Please enter a name (Enter Qor q to quit) " scanf("%s",val); while (vall0]ql val[O]'Q) printf("You have stopped entering valuesin 16. What is output for each of the following for loops? a. for (1-0:1