Answer to Question #231994 in C++ for mahnoor

Question

We want to calculate the total marks of each student of a class in Physics,Chemistry and Mathematics and the average marks of the class. The number of students in the class are entered by the user. Create a class named Marks with data members for roll number, name and marks. Create three other classes inheriting the Marks class, namely Physics, Chemistry and Mathematics, which are used to define marks in individual subject of each student. Roll number of each student will be generated automatically.

Answer 1

#include<iostream>
using namespace std;
class Physics;
class Chemistry;
class Mathematics;
class Marks{
	protected:
		int rollno;
		string name;
		int marks[3];
	public:
		Marks(){
		}
		Marks(int roll, string n){
			rollno = roll;
			name = n;
		}
		void display(){
			cout<<"Roll Number:   "<<rollno<<" \n ";
			cout<<"Name:     "<<name<<" \n ";
		
		}
		friend int getTotalMarks(Marks &, Physics&, Chemistry&,  Mathematics&);
};
 class Physics: public Marks{
 	private:
 		int mark;
 	public:
 		Physics(){
		 }
 		Physics(int mark){
 			this->mark = mark;
		 }
		 friend int getPhysicsMarks(Physics &);
 	
 };
 class Chemistry: public Marks{
 		private:
 		int mark;
 	public:
 		Chemistry(){
		 }
 		Chemistry(int mark){
 			this->mark = mark;
		 }
		 friend int getChemistryMarks(Chemistry &);
 	
 	
 }; 
 class Mathematics: public Marks{
 	private:
 		int mark;
 	public:
 		Mathematics(){
		 }
 		Mathematics(int mark){
 			this->mark = mark;
		 }
		 friend int getMathematicsMarks(Mathematics &);
 };
 //The function to return Physics marks
  int getPhysicsMarks(Physics &p){
 	
 	
 	return p.mark;
 }
 //The function to return Chemistry marks
  int getChemistryMarks(Chemistry &c){
 	
 	
 	return c.mark;
 }
 //The function to return Mathematics mark
 int getMathematicsMarks(Mathematics &m){
 	
 	
 	return m.mark;
 }
 
 int getTotalMarks(Marks&ma,Physics&p, Chemistry&c,  Mathematics&m){
 	
 	int first = getPhysicsMarks(p);
 	int second = getChemistryMarks(c);
 	int third = getMathematicsMarks(m);
 	ma.marks[0] = first;
 	ma.marks[1] = second;
 	ma.marks[2] = third;
 	int sum = 0.0;
 	for(int i=0; i<3; i++){
 		sum += ma.marks[i];
	 }
 	return sum;
 }
int main(){


int n;
cout<<"Enter the total number of students in the class\n";
cin>>n;
double totalSum = 0.0;
int physics;
int chemistry;
int maths;
string name;
Marks marks[n];
double total [n];
for(int i=0; i<n; i++){
	cout<<"Student "<<(i+1)<<endl;
	cout<<"Enter the student name:  "<<endl;
	cin>>name;
	Marks J(i+1,name);
	marks[i] = J;
	cout<<"Enter the student Physics marks:  "<<endl;
	cin>>physics;
	cout<<"Enter the student Chemistry marks:  "<<endl;
	cin>>chemistry;
	cout<<"Enter the student Mathematics marks:  "<<endl;
	cin>>maths;
	Physics p1(physics);
Chemistry c1(chemistry);
Mathematics m1(maths);
	total[i] = getTotalMarks(marks[i],p1,c1,m1);
	
}


for(int i=0; i<n; i++){
	cout<<"Student:   "<<(i+1)<<endl;
	marks[i].display();
	cout<<"Total  marks:   "<<total[i]<<endl;
}
double average = 0.0;
for(int i=0; i<n; i++){
	totalSum += total[i];
}
cout<<"Total marks of the class is:   "<<totalSum<<"\nThe average marks of the class is:    "<<totalSum /n;


}