Exercise 1: Complete the program by filling in the code (areas in bold). This problem requires that you study very carefully the code and the data file already written to prepare you to complete the program. Notice that in the data file the names occupy no more than 15 characters. Why? Exercise 2: Add another field called letter to the record which is a character that holds the letter grade of the student. This is based on the average of the grades as follows: test1 and test2 are each worth 30% of the grade while final is worth 40% of the grade. The letter grade is based on a 10 point spread. The code will have to be expanded to find the average. 90–100 A 80–89 B 70–79 C 60–69 D 0–59 F

A-12.3 an american spy is deep undercover in the hostile country of phonemia. in order not to waste scarce resources, any time he wants to send a message back home, he removes all the punctuation from his message and converts all the letters to uppercase. so, for example, to send the message, “abort the plan! meet at the dark cabin.” he would transmit given such a string, s, of n uppercase letters, describe an efficient way of breaking it into a sequence of valid english words. you may assume that you have a function, valid(s), which can take a character string, s, and return true if and only if s is a valid english word. what is the running time of your algorithm, assuming each call to the function, valid, runs in o(1) time?