Question

I have a C++ code that lets me enter, display and delete a student record. I need to implement a function that prints the average grade score of the students I input.

Below is my code and a picture of how my code looks right now.

#include<iostream>
#include<stdlib.h>
using namespace std;
//Node Declaration
struct node
{
   string name;
   string id;
   int score;
   node *next;  
};
//List class
class list
{
       private:
       //head represents start node, tail represent last node
       node *head, *tail;
       public:
       list()
       {
           head=NULL;
           tail=NULL;
       }
       void createnode(string name,string id,int score)
       {
           //Create a new node temp with passed data
           node *temp=new node;
           temp->name=name;
           temp->id=id;
           temp->score=score;
           temp->next=NULL;
           //If list is empty then temp will be the node
           if(head==NULL)
           {
               head=temp;
               tail=temp;
               temp=NULL;
           }
           //append temp at end of the list
           else
           {  
               tail->next=temp;
               tail=temp;
           }
       }
       void display(string id)
       {
           node *temp=new node;
           temp=head;
           //Traverse entire list
           while(temp!=NULL)
           {
               //if We found the key print details and returns
               if(temp->id==id)
               {
                   cout<<"Name:"<<temp->name<<endl;
                   cout<<"ID:"<<temp->id<<endl;
                   cout<<"Grade:"<<getGrade(temp->score)<<endl;
                   return;
               }
               //Move to next node
               temp=temp->next;
           }
           //We come here when key is not found
           cout << "ID not found";
       }
       //Funcntion for grading
       string getGrade(int score)
       {
           if(score<=100 && score>=93)
               return "A";
           else if(score<=92 && score>=90)
               return "A-";
           else if(score<=89 && score>=87)
               return "B+";
           else if(score<=86 && score>=83)
               return "B-";
           else if(score<=79 && score>=77)
               return "C+";
           else if(score<=76 && score>=73)
               return "C";
           else if(score<=72 && score>=70)
               return "C-";
           else if(score<=69 && score>=67)
               return "D+";
           else if(score<=66 && score>=60)
               return "D";
           else
               return "F";
       }
       void deleteRecord(string id)
       {
           node *temp=new node;
           node *prev=new node;
           temp=head;
           //If id at head, move head to next node
           if(temp!=NULL && temp->id==id)
           {
               head=temp->next;
               free(temp);
               return;
           }
           //iterate untill id found
           while (temp != NULL && temp->id != id)
            {
                prev = temp;
                temp = temp->next;
            }
            //we come here when id not found
           if(temp==NULL)
           {
               cout << "ID not found";
               return;
           }
           //delete temp node
           prev->next=temp->next;
           free(temp);           
       }
};
int main()
{
   list obj;
   int choice,score;
   string name,id;
   while(true)
   {
       cout << "\n1.Insert\n2.Display\n3.Delete\n4.exit: ";
       cin >> choice;
       if(choice==1)
       {
           cout << "Enter name: ";
           cin >> name;
           cout << "Enter id: ";
           cin >> id;
           cout << "Enter score: ";
           cin >> score;
           obj.createnode(name,id,score);
       }
       else if(choice==2)
       {
           string searchId;
           cout << "Enter ID to Display: ";
           cin >> searchId;
           obj.display(searchId);
       }
       else if(choice==3)
       {
           string searchID;
           cout << "Enter ID to delete record: ";
           cin >> searchID;
           obj.deleteRecord(searchID);
       }
       else
           break;
   }
   return 0;
}

Insert Display Delete exit: 1 nter name Eswar Enter id 1 nter score: 78 Insert Display Delete exit: 1 nter name Aruna Enter id2 nter score: 76 Insert Display Delete exit: 1 nter name Akhi Enter id3 nter score: 99 Insert Display Delete exit 2 nter ID to Display: 3 Name Akhi ID:3 rade H . Insert Display Delete 4.exit: 2 Enter ID to Display: 4 ID not found . Insert Display Delete 4.exit: 3 Enter ID to delete record: 5 ID not found . Insert Display Delete exit:

Answer 1

Program.cpp

#include<iostream>
#include<stdlib.h>
using namespace std;
//Node Declaration
struct node
{
string name;
string id;
int score;
node *next;
};
//List class
class list
{
private:
//head represents start node, tail represent last node
node *head, *tail;
public:
list()
{
head=NULL;
tail=NULL;
}
void createnode(string name,string id,int score)
{
//Create a new node temp with passed data
node *temp=new node;
temp->name=name;
temp->id=id;
temp->score=score;
temp->next=NULL;
//If list is empty then temp will be the node
if(head==NULL)
{
head=temp;
tail=temp;
temp=NULL;
}
//append temp at end of the list
else
{
tail->next=temp;
tail=temp;
}
}
void display(string id)
{
node *temp=new node;
temp=head;
//Traverse entire list
while(temp!=NULL)
{
//if We found the key print details and returns
if(temp->id==id)
{
cout<<"Name:"<<temp->name<<endl;
cout<<"ID:"<<temp->id<<endl;
cout<<"Grade:"<<getGrade(temp->score)<<endl;
return;
}
//Move to next node
temp=temp->next;
}
//We come here when key is not found
cout << "ID not found";
}
//Funcntion for grading
string getGrade(int score)
{
if(score<=100 && score>=93)
return "A";
else if(score<=92 && score>=90)
return "A-";
else if(score<=89 && score>=87)
return "B+";
else if(score<=86 && score>=83)
return "B-";
else if(score<=79 && score>=77)
return "C+";
else if(score<=76 && score>=73)
return "C";
else if(score<=72 && score>=70)
return "C-";
else if(score<=69 && score>=67)
return "D+";
else if(score<=66 && score>=60)
return "D";
else
return "F";
}
void deleteRecord(string id)
{
node *temp=new node;
node *prev=new node;
temp=head;
//If id at head, move head to next node
if(temp!=NULL && temp->id==id)
{
head=temp->next;
free(temp);
return;
}
//iterate untill id found
while (temp != NULL && temp->id != id)
{
prev = temp;
temp = temp->next;
}
//we come here when id not found
if(temp==NULL)
{
cout << "ID not found";
return;
}
//delete temp node
prev->next=temp->next;
free(temp);   
}
void average_grade_score(){//calculate average
node *temp=new node;
int avg=0,length=0;
temp=head;
//Traverse entire list
while(temp!=NULL)
{
avg+=temp->score;
temp=temp->next;
length++;
  
}
cout<<"Average is: "<<avg/length;
}
};
int main()
{
list obj;
int choice,score;
string name,id;
while(true)
{
cout << "\n1.Insert\n2.Display\n3.Delete\n4.Calculate Average\n5.exit: ";
cin >> choice;
if(choice==1)
{
cout << "Enter name: ";
cin >> name;
cout << "Enter id: ";
cin >> id;
cout << "Enter score: ";
cin >> score;
obj.createnode(name,id,score);
}
else if(choice==2)
{
string searchId;
cout << "Enter ID to Display: ";
cin >> searchId;
obj.display(searchId);
}
else if(choice==3)
{
string searchID;
cout << "Enter ID to delete record: ";
cin >> searchID;
obj.deleteRecord(searchID);
}else if (choice == 4){
obj.average_grade_score();
}
else
break;
}
return 0;
}

Output

null