////////////////////////////////////////////////////////////////////////////////
// School of Computing, Universiti Teknologi Malaysia
// SECJ1013- Programming Technique I
// Semester 1, 2020/2021
// ASSIGNMENT III
// 11 Jan 2021
// Pair information 
// Name: Gui Yu Xuan
// Matrics No: A20EC0039
// Section: 01
// Name: Nurzarifah Binti Azizan
// Matrics No: A20EC0127
// Section: 01
//
////////////////////////////////////////////////////////////////////////////////

#include<iostream>
#include<cstdlib>
#include<fstream>
#include<iomanip>
#include<limits>

using namespace std;

#define MAXSTREAM numeric_limits<streamsize>::max()

//------------------------------------------------------------------------------------
// Function : readFile  
// Purpose  : To read inputs from a file consisting of the list of patient's name along 
//            with their weights and heights of the patient.
// Parameters:
//           name	   :  the array to hold the list of patient's names read from the file
//           weight    :  the array to hold the list of weights
//           height    :  the array to hold the list of heights
//           count     :  the number of patients read
//------------------------------------------------------------------------------------

// Task 1: Complete the definition of function "readFile"          (10 marks)

void readFile(char name[][20], double weight[], double height[], int &count)
{
	char nm[20];   // patient's name
	double wgt;    // patient's weight
	double hgt;    // patient's height

	ifstream inputFile; 

	//  complete these lines to open the input file, check the input file whether it is exist or not and display the error message (input validation).
	inputFile.open("input.txt");
	
	if (!inputFile.is_open())
	{
	cout << "ERROR: Cannot open file\n";;
	exit(1);
	}

	count = 0;
	while (inputFile.getline (nm, 20, '\t'))
	{

		inputFile >> wgt; 
		inputFile >> hgt; 
		inputFile.ignore(MAXSTREAM, '\n');  //ignore newline

		// complete these lines to store the read data into arrays accordingly and close the open file.
		
		for (int i=0; i<20; i++)
		{
			
			name[count][i]=nm[i];
			
		}

		weight [count] = wgt;
		height [count] = hgt;

		count++;
	}
	
	inputFile.close();
	
}

//------------------------------------------------------------------------------------
// Function  : convertMeter
// Purpose   : To convert centimeter to meter
//
// Parameters:
//         	a  - the input array
//			b  - the array that holds the results of meter
//          n  - the size of array 
//
//------------------------------------------------------------------------------------

// Task 2 : Complete the definition of function convertMeter  (5 marks)

void convertMeter(double a[], double b[], int n)
{
	for(int i=0;i<n;i++)
	{
		b[i]=a[i]/100;
	}

}

//------------------------------------------------------------------------------------
// Function  : calculateBMI
// Purpose   : to calculate the elements of arrays x and y correspondingly using BMI formula, and puts the result into another array, z.
//             BMI formula: weight(kg) / (height(m) * height (m))
// Parameters:
//      		x,y  - the input arrays
//              z    - the array that holds the results of the calculation.
//------------------------------------------------------------------------------------
// Task 3 : Complete the defintion of function calculateBMI  (7 marks)

void calculateBMI(const double x[], const double y[], double z[], int n)
{
	for (int i=0;i<n;i++)
	{
		z[i]=x[i]/(y[i]*y[i]);
	}

}

//------------------------------------------------------------------------------------
// Function  : average
// Purpose   : To calculate the average elements of an array.
//
// Parameters:
//         	a  - the array
//          n  - the size of array 
//
//  Return value:  the average of all the elements of the array
//------------------------------------------------------------------------------------

// Task 4 : Complete the definition of function average  (8 marks)

double average(const double a[], int n)
{
	double sum = 0, ave = 0; 
	
	for(int i=0;i<n;i++)
	{
		sum+=a[i];
	}
	
	ave+=(sum/n);
	
	return ave;

}



int main()
{
	char pName[10][20];  	// The list (array) of patient's names
	double pWeight[10]; 	// The list (array) of patient's weights
	double pHeight[10];  	// The list (array) of patient's heights in cm
	double pMeter[10];  	// The list (array) of patient's heights in meter  
	double pBMI[10]; 		// The list of BMI, i.e.,weight / (height x height)
	double aveWgt;    		// Total average weight for all patients
	int n;   				// The number of patients	

	
	
	// Task 5: Using all the functions defined above, write a function call, 
	//(a) to read file from the input file, (b) to convert meter, (c) to calculate BMI and (d) to calculate average of weights. (9 mark)

	readFile (pName,  pWeight,  pHeight, n);
	convertMeter(pHeight,  pMeter, n);
	calculateBMI(pWeight, pMeter,  pBMI, n);
	aveWgt = average(pWeight, n);	
	
	
    // Task 6: Print the list of patient's names along with their weight, height in meter and the calculated BMI to the output file (output.txt). (16 marks)
	// You should open and close the output file, and use proper formatting output.

	cout << "Writing to the output file... " << endl;
	
	ofstream outputFile;
	
	outputFile.open("output.txt");
	
	outputFile<<"Name "
	<<setw(24)<<"Weight(kg)"
	<<setw(13)<<"Height(m)"
	<<setw(7)<<"BMI"<<endl;
	
	int list=0;
	
	while(list!=n)
	{
		
		outputFile<<setw(19)<<left<<pName[list];
		outputFile<<fixed<<setprecision(2);
		outputFile<<setw(14)<<pWeight[list]
		<<setw(13)<<pMeter[list]
		<<setw(10)<<pBMI[list]<<endl;
		list++;

	}
	
	outputFile<<endl;
	
	outputFile.close();


    // Task 7: Print the number of patients and the average weight of all patients to the program screen. (5 marks).

	cout<<showpoint<<fixed<<setprecision(1)<<endl;
	cout<<"Number of patients : "<<n<<endl;
	cout<<"Average weight\t: "<<aveWgt<<endl;


	return 0;
}


// Reflection 
// I understand the concept and I can do the basic coding. But when the question change a liitle bit, I can't answer.
// I don't know how to apply the things that I had learned.