Question

Professor realizes that he hates his class and has decided to give each of his students a 20-point decrease in all their grades for no reason. Help him write the C++ code that will allow him to do this.

Consider the code on the next page. It creates an array of 10 structs called students which contains their name and their grade. It is nearly complete. Your task is the following:

1. Complete the user-defined function called subtractTwenty.
   1. You will need to create a for-loop that iterates through the 10 students and subtract 20 from their grade.
   2. A student cannot have a grade lower than 0. If their grade falls below 0, you must set it equal to 0

      #include <iostream>

      using namespace std;

      //struct that creates student

      struct student

      {

           string name;

           int grade;

      };

      //user-defined function prototypes

      void subtractTwenty(student[10]);

      void printArray(student[10]);

      int main()

      {

           //array of 10 students

           student arrayOfStudents[10];

           //populate the 10 students

           arrayOfStudents[0] = { "Alice", 78 };

           arrayOfStudents[1] = { "Bobby", 90 };

           arrayOfStudents[2] = { "Casey", 44 };

           arrayOfStudents[3] = { "Devon", 57 };

           arrayOfStudents[4] = { "Ethan", 12 };

           arrayOfStudents[5] = { "Frank", 99 };

           arrayOfStudents[6] = { "Grace", 70 };

           arrayOfStudents[7] = { "Heidi", 80 };

           arrayOfStudents[8] = { "Isaac", 14 };

           arrayOfStudents[9] = { "Jason", 40 };

           cout << endl << "Before subtracting 20: " << endl << endl;

           printArray(arrayOfStudents);

           subtractTwenty(arrayOfStudents);

           cout << endl << "After subtracting 20: " << endl << endl;

           printArray(arrayOfStudents);

           cout << endl << endl;

           return 0;

      }

      void subtractTwenty(student a[10])

      {

      }

      void printArray(student a[10])

      {

           for (int i = 0; i < 10; i++)

           {

                 cout << "Name: " << a[i].name << ", Grade: " << a[i].grade << endl;

           }

      }

Answer 1

Updated code is as follows:

#include <iostream>
using namespace std;

//struct that creates student
struct student
{
    string name;
    int grade;
};

//user-defined function prototypes
void subtractTwenty(student[10]);
void printArray(student[10]);

int main()
{
    //array of 10 students
    student arrayOfStudents[10];

    //populate the 10 students
    arrayOfStudents[0] = { "Alice", 78 };
    arrayOfStudents[1] = { "Bobby", 90 };
    arrayOfStudents[2] = { "Casey", 44 };
    arrayOfStudents[3] = { "Devon", 57 };
    arrayOfStudents[4] = { "Ethan", 12 };
    arrayOfStudents[5] = { "Frank", 99 };
    arrayOfStudents[6] = { "Grace", 70 };
    arrayOfStudents[7] = { "Heidi", 80 };
    arrayOfStudents[8] = { "Isaac", 14 };
    arrayOfStudents[9] = { "Jason", 40 };
  
    cout << endl << "Before subtracting 20: " << endl << endl;
    printArray(arrayOfStudents);
    subtractTwenty(arrayOfStudents);
    cout << endl << "After subtracting 20: " << endl << endl;
    printArray(arrayOfStudents);
    cout << endl << endl;
    return 0;
}

void subtractTwenty(student a[10])
{
    for (int i = 0; i < 10; i++)
    {
        a[i].grade-=20;
        if(a[i].grade<0)
        {
            a[i].grade=0;
        }
    }
}

void printArray(student a[10])
{
    for (int i = 0; i < 10; i++)
    {
        cout << "Name: " << a[i].name << ", Grade: " << a[i].grade << endl;
    }
}
Sample output:

Mention in comments if any mistakes or errors are found. Thank you.