Rewrite the program of Fig. 6.22 to use a menu-driven interface. The program should offer the user four options as follows:

Enter a choice:

0 Print the array of grades

1 Fine the minimum grade

2 Find the maximum grade

3 Print the average on all tests for each student

4 End Program

One restriction on using arrays of pointers to functions is that all the pointers must have the same type. The pointers must be to functions of the same return type that receive arguments of the same type. For this reason, the functions in Fig. 6.22 must be modified so that they each return the same type and take the same parameters. Modify functions minimum and maximum to print the minimum or maximum value and return nothing. For option 3, modify function average of Fig. 6.22 to output the average for each student (not a specific student). Function average should return nothing and take the same parameters as printArray, minimum and maximum. Store the pointers to the four functions in array processGrades and use the choice made by the user as the subscript into the array for calling each function. (You may think of using the following definitions and predefine the students grades in a 2D array:)

#define STUDENTS 3

#define EXAMS 4

void minimum(unsigned int grades[][EXAMS], size_t pupils, size_t tests);

void maximum(unsigned int grades[][EXAMS], size_t pupils, size_t tests);

void average(unsigned int grades[][EXAMS], size_t pupils, size_t tests);

void printArray(unsigned int grades[][EXAMS], size_t pupils, size_t tests);

void printMenu(void);

Fig06_22.c

// Two-dimensional array manipulations. #include #define STUDENTS 3 #define EXAMS 4

// function prototypes int minimum(const int grades[][EXAMS], size_t pupils, size_t tests); int maximum(const int grades[][EXAMS], size_t pupils, size_t tests); double average(const int setOfGrades[], size_t tests); void printArray(const int grades[][EXAMS], size_t pupils, size_t tests);

// function main begins program execution int main(void) { // initialize student grades for three students (rows) int studentGrades[STUDENTS][EXAMS] = { { 77, 68, 86, 73 }, { 96, 87, 89, 78 }, { 70, 90, 86, 81 } };

// output array studentGrades puts("The array is:"); printArray(studentGrades, STUDENTS, EXAMS);

// determine smallest and largest grade values printf(" Lowest grade: %d Highest grade: %d ", minimum(studentGrades, STUDENTS, EXAMS), maximum(studentGrades, STUDENTS, EXAMS));

// calculate average grade for each student for (size_t student = 0; student < STUDENTS; ++student) { printf("The average grade for student %u is %.2f ", student, average(studentGrades[student], EXAMS)); } }

// Find the minimum grade int minimum(const int grades[][EXAMS], size_t pupils, size_t tests) { int lowGrade = 100; // initialize to highest possible grade

// loop through rows of grades for (size_t i = 0; i < pupils; ++i) {

// loop through columns of grades for (size_t j = 0; j < tests; ++j) {

if (grades[i][j] < lowGrade) { lowGrade = grades[i][j]; } } }

return lowGrade; // return minimum grade }

// Find the maximum grade int maximum(const int grades[][EXAMS], size_t pupils, size_t tests) { int highGrade = 0; // initialize to lowest possible grade

// loop through rows of grades for (size_t i = 0; i < pupils; ++i) {

// loop through columns of grades for (size_t j = 0; j < tests; ++j) {

if (grades[i][j] > highGrade) { highGrade = grades[i][j]; } } }

return highGrade; // return maximum grade }

// Determine the average grade for a particular student double average(const int setOfGrades[], size_t tests) { int total = 0; // sum of test grades // total all grades for one student for (size_t i = 0; i < tests; ++i) { total += setOfGrades[i]; } return (double) total / tests; // average }

// Print the array void printArray(const int grades[][EXAMS], size_t pupils, size_t tests) { // output column heads printf("%s", " [0] [1] [2] [3]");

// output grades in tabular format for (size_t i = 0; i < pupils; ++i) {

// output label for row printf(" studentGrades[%u] ", i);

// output grades for one student for (size_t j = 0; j < tests; ++j) { printf("%-5d", grades[i][j]); } } }