Edit an Inputted user information

[Vandalism]

A user will input multiple entries and every entry will be labeled as entry no. 1/no. 2 and so on...
When a user wants to edit an entry, he/she will pick the entry number and that would change the whole information.
The problem is when I edit an entry, it would always change the last entry not its entry number.
Do you guys know how to fix this?
Thank You!

  #include<iostream>
#include<string>
#include<cstdlib>
#include<cstdio>
#include<iomanip>
using namespace std;

struct Person
{
	char fname[100];
	char lname[100];
	char cnum[15];
	string address;
};

void AddEntry(Person p);
void DisplayEntry();
void EditEntry(Person *);
void line(char, int);
void newLine();

Person person[20];
Person p;
int index = 0;

int main()
{
	int option;
	while (1) {
		system("cls");
		system("COLOR D");
		cout << "-------------------Address Book";
		line('-', 19);
		cout << "\n           What would you like to do?\n";
		line('-', 50);
		cout << "                [1] Add Contact \n";
		cout << "                [2] Edit Contact \n";
		cout << "                [3] Delete Contact \n";
		cout << "                [4] View Contacts \n";
		cout << "                [5] Search Address Book \n";
		cout << "                [6] Exit \n";
		line('-', 50);
		cout << "Please enter your choice: ";
		cin >> option;
		newLine();
		char buff[2];
		switch (option)
		{
		case 1:
			system("cls");
			system("COLOR B");
			cout << "Enter First Name: ";
			cin.getline(p.fname, 100);
			cout << "Enter Last Name: ";
			cin.getline(p.lname, 100);
			cout << "Enter Address: ";
			cin >> p.address;
			newLine();
			cout << "Enter Contact Number: ";
			cin >> p.cnum;
			newLine();
			AddEntry(p);
			break;
			case 2:
				EditEntry(person);
				break;
			//case 3:
			//	/*DeleteEntry();*/
			//	break;
		case 4:
			DisplayEntry();
			break;
			//case 5:
			//	/*SearchEntry();*/
			/*	break;*/
		case 6:
			exit(1);
		default:
			cout << "Invalid choice \n\n";
			system("pause>0");
		}
	}
	return 0;
}

void AddEntry(Person p)
{
	person[index] = p;
	index++;
}

void DisplayEntry()
{
	system("cls");
	system("COLOR E");
	cout << setw(11) << "No." << setw(10)
		<< "   First Name" << setw(10)
		<< "   Last Name" << setw(18)
		<< "Address" << setw(10)
		<< "   Contact No." << setw(10);

	cout.setf(ios::fixed);
	cout.setf(ios::showpoint);
	cout.precision(2);

	int i = 0;
	for (; i < index; i++){
		cout << endl;
		cout << i + 1 << setw(10);
		cout << person[i].fname << setw(10);
		cout << person[i].lname << setw(18);
		cout << person[i].address << setw(10);
		cout << person[i].cnum <<setw(10);
	}
	printf("\nRecords Total:%d\n", i);
	system("pause>0");
}

void EditEntry(Person *p)
{
	system("cls");
	system("COLOR A");
	int a;
	cout << "Enter the entry number you would like to edit: ";
	cin >> a;
	newLine();
	if (a <= 100)
	{
		cout << endl;
		cout << "Please enter the updated information: ";
		cout << "\nEnter First Name: ";
		cin.getline(p[a].fname, 100);
		cout << "Enter Last Name: ";
		cin.getline(p[a].lname, 100);
		cout << "Enter Address: ";
		cin >> p[a].address;
		newLine();
		cout << "Enter Contact Number: ";
		cin >> p[a].cnum;
		newLine();
	}
	else{
		cout << "I'm sorry, that is an invalid selection.\n"
			<< "The number of entry is ranging from 0-100.\n"
			<< "Please select this option again.\n\n";
	}

}


void line(char ch, int ctr)
{
	for (int i = 0; i < ctr; i++) {
		cout << ch;
	}
	cout << endl;
}

void newLine()
{
	char s; do{
		cin.get(s);
	} while (s != '\n');
}

[shadowCODE]

The user starts counting from 1. So if he wants to edit Index 1, he will input a = 1.
in your code, you edite p[a] which is instead the next record.

Edit p[a-1] instead.

[Vandalism]

Thank you! I really appreciate it. It now works!

void EditEntry(Person *p)
{
	system("cls");
	system("COLOR A");
	int a = 1;
	cout << "Enter the entry number you would like to edit: ";
	cin >> a;
	newLine();
	if (a <= 100)
	{
		cout << endl;
		cout << "Please enter the updated information: ";
		cout << "\nEnter First Name: ";
		cin.getline(p[a - 1].fname, 100);
		cout << "Enter Last Name: ";
		cin.getline(p[a - 1].lname, 100);
		cout << "Enter Address: ";
		cin >> p[a - 1].address;
		newLine();
		cout << "Enter Contact Number: ";
		cin >> p[a - 1].cnum;
		newLine();
	}
	else{
		cout << "I'm sorry, that is an invalid selection.\n"
			<< "The number of entry is ranging from 0-100.\n"
			<< "Please select this option again.\n\n";
	}

}