//Exercise 5.5 Calculating average student grades.#include <stdio.h>#include <stdbool.h>#include <ctype.h>int main(void){  size_t nclasses = 0;                  // Number classes  size_t nstudents_max = 0;             // Maximum number of students in a class  char answer = ‘N‘;  printf("How many students are in the largest class? :");  scanf("%zd", &nstudents_max);  printf("How many classes are there? :");  scanf("%zd", &nclasses);  size_t class = 0;  size_t student = 0 ;  int grades[nclasses][nstudents_max];                     // Stores the grades  size_t students[nclasses];                               // Stores the number of students in each class  for( class = 0 ; class < nclasses ; ++class)    {    printf("Enter the grades for students in class %zd.\n", class + 1);    students[class] = 0;                                   // Student count within a class    while(true)    {      printf("Enter the integer grade for student %zd: ", students[class] + 1);      scanf("%d", &grades[class][students[class]]);      if(++students[class] == nstudents_max)                // Increment and check student count      {        printf("Class %zd complete.", class + 1);        break;      }      printf("Any more students in class %zd (Y or N): ", class + 1);      scanf(" %c", &answer);      if(toupper(answer) == ‘N‘)      break;    }  }  printf("\n");  for( class = 0 ; class < nclasses ; ++class)    {    int class_total = 0;    printf("Student grades for class %zd are:\n", class + 1);    for( student = 0 ; student < students[class] ; ++student)    {      class_total += grades[class][student];      if((student + 1) % 6 == 0)        printf("\n");      printf("%5d", grades[class][student]);    }    printf("\nAverage grade for class %zd is %.2lf\n", class + 1, (double)class_total/students[class]);  }    return 0;}